Showing posts with label combinatorics. Show all posts
Showing posts with label combinatorics. Show all posts

Monday, 6 April 2026

The Sicherman Dice

I'm amazed I've never heard of these dice before. I asked Gemini to create a report on them and here is what it came up with. It's a long read but well worth it.

The Isomorphic Link Between Combinatorics and Statistical Mechanics: A Comprehensive Analysis of the Sicherman Dice

Introduction

In the intricate landscape of applied mathematics and theoretical physics, the pursuit of understanding randomness frequently reveals profound structural symmetries between entirely disparate disciplines. Phenomena that initially present as isolated curiosities in discrete combinatorics often harbor the underlying mathematical architecture required to resolve fundamental questions in statistical thermodynamics. The most striking contemporary example of such an interdisciplinary bridge is the paradigm of the Sicherman dice. Discovered in the late 1970s, this unique pair of six-sided dice possesses a highly counterintuitive algebraic property. Despite bearing an unconventional arrangement of positive integers upon their faces, the act of rolling the two Sicherman dice and summing their uppermost values yields a discrete probability distribution that is entirely indistinguishable from that of a standard pair of fair, six-sided dice.

For decades following their initial discovery, the Sicherman dice were predominantly celebrated as an elegant artifact of recreational mathematics—a testament to the precise mechanics of polynomial factorization. The geometric and algebraic constraints required to produce such an anomaly provided a fertile testing ground for combinatorial theorists investigating the properties of cyclotomic polynomials and multi-sided platonic solids. However, the theoretical utility of the Sicherman arrangement has recently transcended its recreational origins. Breakthrough research at the intersection of mathematical physics and economic decision theory has repurposed the foundational algebra of these "crazy dice" to definitively characterize the Boltzmann distribution. By treating the polynomial representations of the Sicherman dice as a mathematical stress test for the independence of uncoupled probability systems, physicists have succeeded in proving that the 150-year-old Boltzmann distribution is the singular mathematical framework capable of describing thermodynamic equilibrium without generating paradoxical correlations.

This exhaustive research report provides a definitive, expert-level examination of the Sicherman dice. It comprehensively traces the historical narrative of their discovery, rigorously deconstructs the mathematical proofs governing their unique probability distribution via the factorization of polynomial generating functions, and explores the profound macroscopic implications of these combinatorial concepts. Specifically, the analysis will elucidate how the algebra of alternative dice arrangements serves to validate the foundational laws of statistical mechanics, the calculation of the partition function, and the structural integrity of the multinomial logit model in economic theory.

Historical Context and Discovery

The history of the Sicherman dice is deeply embedded in the late-twentieth-century renaissance of recreational mathematics, a period characterized by a vibrant exchange of ideas between academic mathematicians, hobbyists, and puzzle creators. The central figure in this narrative is Colonel George Sicherman, a puzzle creator, mathematics enthusiast, and programmer operating out of Buffalo, New York.

The Gardner Correspondence

The theoretical genesis of the Sicherman dice occurred during a sporadic but highly influential correspondence between George Sicherman and Martin Gardner, the legendary author of the "Mathematical Games" column in Scientific American. During the mid-1970s, Gardner's column served as the premier international forum for disseminating novel mathematical curiosities. Between 1976 and 1977, Sicherman and Gardner exchanged several communications regarding hypothetical probability spaces.

In a pivotal letter dated January 27, 1977, Sicherman formalized a proposition involving a hypothetical pair of six-sided dice whose numerical spots were radically rearranged. Sicherman's design dictated that the first die would bear the positive integers 1, 2, 2, 3, 3, and 4 on its six faces. The second die would be numbered with the integers 1, 3, 4, 5, 6, and 8. Sicherman demonstrated to Gardner that despite this highly unconventional topological arrangement, the sum of the faces when both dice were thrown in tandem would produce exactly the same probability distribution for the outcome integers 2 through 12 as a conventional pair of dice numbered 1 through 6.

Gardner immediately grasped the algebraic elegance and rarity of this proposition. He subsequently introduced the concept to the broader scientific community in his February 1978 column in Scientific American, officially codifying the mathematical anomaly under the eponymous title "Sicherman Dice". In his writings, Gardner meticulously noted that Sicherman had not merely stumbled upon this arrangement through trial and error, but had successfully formulated a rigorous algebraic proof. Sicherman had demonstrated that the only sets of three or more dice capable of rolling the same probabilistic result distributions as standard dice are standard dice themselves, pairs of Sicherman dice, or any combination thereof.

The historical record contains an interesting corollary regarding the origination of the concept. Gardner later mentioned in a subsequent letter to Sicherman that an unnamed magician of his acquaintance had theoretically anticipated the possibility of such a numerical discovery. However, the magician lacked the mathematical formalism to prove the uniqueness of the arrangement; it was unequivocally Sicherman who formalized the discovery and proved the algebraic isolation of this specific numerical set.

Academic Proliferation and Generalization

The formal publication of the Sicherman dice in Scientific American acted as an immediate catalyst for academic inquiry into the underlying properties of renumbered polyhedra. In 1979, the discovery inspired the publication of several foundational scholarly papers in the field of combinatorial mathematics. Most notable among these early works were "Cyclotomic Polynomials and Nonstandard Dice" by Joseph A. Gallian and David J. Rusin, and "Renumbering of the Faces of Dice" by Duane Broline.

These papers seized upon Sicherman's core methodology, abstracting the concept to explore alternative labelings for other platonic solids, such as four-sided, eight-sided, and twenty-sided dice. The academic momentum continued into the subsequent decades, generating further generalizations of the Sicherman paradigm to non-cubical geometries and multi-dice systems, as evidenced by the later scholarly contributions of Brunson and Swift in 1997 and Fowler and Swift in 1999.

Commercialization and Physical Production

Parallel to the rigorous academic exploration of the concept, the Sicherman dice transitioned into the realm of physical production and commercial game theory. The first known physical pair of these non-standard dice was custom-crafted specifically for George Sicherman by George & Co., a local purveyor in Buffalo.

Decades later, with the proliferation of internet-based niche commerce, the dice became widely accessible to educators, statisticians, and tabletop gaming enthusiasts. By 2009, prominent suppliers such as Gamestation.net began offering them commercially as a mixed pair to avoid confusion with standard dice. In these sets, the die bearing the sequence 1–2–2–3–3–4 was typically cast in blue, while the die bearing the sequence 1–3–4–5–6–8 was cast in green.

Concurrently, another supplier, Grand Illusions, Ltd., recognized a physical limitation in the traditional design: arranging eight distinct, symmetrical pips on the finite surface area of a standard die face is visually clustered and challenging to read at a glance. Consequently, they produced a white pair of Sicherman dice that utilized clear Arabic numerals instead of traditional pips. While companies like Gamestation.net and Grand Illusions eventually ceased production or went out of business, the persistent educational demand for the dice ensured their survival in the market. Today, various specialized mathematical and gaming supply companies, including Maths Gear, The Dice Shop, and Noble Knight Games, continue to manufacture and distribute Sicherman dice to institutions and enthusiasts worldwide.

Combinatorics and Applied Probability Spaces

To fully appreciate the mathematical paradox embodied by the Sicherman dice, one must first deconstruct the foundational probability mechanics of standard dice. The architecture of discrete probability spaces defines how finite combinatorial systems operate under randomization. When an individual rolls two standard six-sided dice, each independently labeled with the positive integers 1, 2, 3, 4, 5, and 6, the addition of their uppermost faces produces a discrete integer output ranging from 2 to 12.

Assuming that each die is a fair, uniformly balanced cube, each of the 36 possible combinatorial macro-states (6 independent faces multiplied by 6 independent faces) has a strictly equal probability of occurrence, exactly $\frac{1}{36}$. However, the sum of these faces constitutes a dependent variable that is not uniformly distributed. Multiple distinct combinations can yield the exact same integer sum. This dependency creates a discrete probability distribution characterized by a symmetrical, triangular shape that peaks precisely at the central sum of 7.

Standard Dice Distribution Topography

The precise distribution of expected sums for two standard dice can be calculated through a fundamental addition matrix, which yields the following combinatorial frequencies:

Sum Standard Combinatorial Pairs Number of Ways Expected Probability
2(1,1)11/36
3(1,2), (2,1)22/36
4(1,3), (2,2), (3,1)33/36
5(1,4), (2,3), (3,2), (4,1)44/36
6(1,5), (2,4), (3,3), (4,2), (5,1)55/36
7(1,6), (2,5), (3,4), (4,3), (5,2), (6,1)66/36
8(2,6), (3,5), (4,4), (5,3), (6,2)55/36
9(3,6), (4,5), (5,4), (6,3)44/36
10(4,6), (5,5), (6,4)33/36
11(5,6), (6,5)22/36
12(6,6)11/36

Sicherman Dice Distribution Topography

The fundamental combinatorial paradox of the Sicherman dice lies in their ability to generate this exact probability distribution matrix using entirely distinct, asymmetrical integer sets. As previously established, the first Sicherman die is constrained to the sequence $1, 2, 2, 3, 3, 4$, while the second die spans the sequence $1, 3, 4, 5, 6, 8$.

Constructing a rigorous addition table for these two non-standard arrays yields a summation topography that is miraculously identical to the standard baseline. Notably, the values on opposing sides of the physical Sicherman dice maintain an internal symmetry to ensure balance: pairs on opposing sides always sum to equal numbers, specifically 5 for the first die and 9 for the second die.

The resulting probability matrix for the Sicherman pair is formatted as follows:

Sum Sicherman Combinatorial Pairs Number of Ways Expected Probability
2(1,1)11/36
3(1,2), (1,2)*22/36
4(1,3), (1,3)*, (3,1)33/36
5(1,4), (1,4)*, (2,3), (2,3)*44/36
6(1,5), (1,5)*, (2,4), (2,4)*, (3,3)55/36
7(1,6), (1,6)*, (2,5), (2,5)*, (3,4), (4,3)66/36
8(2,6), (2,6)*, (3,5), (4,4), (4,4)*55/36
9(3,6), (4,5), (4,5)*, (1,8)44/36
10(4,6), (2,8), (2,8)*33/36
11(3,8), (3,8)*22/36
12(4,8)11/36

(Note: The asterisks within the combinatorial pairs represent the distinct variations arising from the intentionally duplicated integers on the first die, specifically the 2s and 3s)

The empirical evidence confirms that despite possessing asymmetrical ranges—with the first die reaching an upper bound of only 4, and the second die extending to an upper bound of 8—the specific mathematical convolution of these subsets perfectly replicates the discrete distribution of a standard dice pair.

Applied Game Theory and Strategic Variance

While the macro-distribution of sums is perfectly identical between the two systems, the individual combinatorial mechanics generate profound practical implications in applied probability, specifically within the domain of tabletop gaming and decision theory. The distinct individual face values inherently alter the conditional probabilities of specific micro-events, most notably the probability of rolling identical pairs, colloquially known as "doubles".

In a traditional game system utilizing standard dice, the probability of rolling doubles (1-1, 2-2, 3-3, 4-4, 5-5, 6-6) is exactly $\frac{6}{36}$, which simplifies to $\frac{1}{6}$. However, when operating within the Sicherman probability space, achieving a "double" necessitates that the values of the two distinct dice match exactly. An inspection of the face values reveals that the only integers present on both Sicherman dice simultaneously are 1, 3, and 4.

The calculation of this restricted micro-probability proceeds as follows:

  • To roll a double 1: The first die must roll a 1 (probability 1/6) and the second die must roll a 1 (probability 1/6). The combined probability is 1/36.
  • To roll a double 3: The first die must roll one of its two 3s (probability 2/6) and the second die must roll its single 3 (probability 1/6). The combined probability is 2/36.
  • To roll a double 4: The first die must roll its single 4 (probability 1/6) and the second die must roll its single 4 (probability 1/6). The combined probability is 1/36.

Aggregating these specific outcomes reveals that the total probability of rolling doubles with a Sicherman pair is only $\frac{4}{36}$, or $\frac{1}{9}$. This statistical variance radically alters the strategic equilibrium in complex games such as Backgammon, where rolling doubles traditionally permits a player to move their pieces four times the face value rather than merely twice. The introduction of Sicherman dice fundamentally depresses the expected value of a standard turn. A player utilizing standard dice can mathematically expect to move an average of $\frac{296}{36}$ points per roll. Conversely, a player utilizing Sicherman dice will move an average of only $\frac{274}{36}$ points per roll, due to the sharp reduction in high-value double opportunities.

However, the Sicherman dice introduce alternative strategic advantages that are fundamentally unavailable within a standard probability space. Because the second die contains the integer 8, a player gains the unprecedented ability to move a single piece 8 continuous spaces in a single action. In the defensive theory of Backgammon, if an opponent successfully occupies six consecutive points with their pieces, they create what is known as a "prime"—an impassable barrier. A player utilizing standard dice cannot mathematically pass this barrier with a single isolated move, as standard dice cannot exceed a face value of 6. The Sicherman die user, however, can bypass the barrier entirely by rolling the 8.

Metric Standard Dice Pair Sicherman Dice Pair
Expected Points Per Roll296/36 (~8.22)274/36 (~7.61)
Probability of Rolling Doubles1/6 (16.67%)1/9 (11.11%)
Maximum Single-Die Value68
Capability to Bypass 6-PrimeImpossiblePossible (Roll of 8)

This complex interplay of perfectly equivalent macro-statistics (identical sums) and radically divergent micro-statistics (doubles frequencies and range limits) underscores the deep analytical complexity embedded within algebraic partition structures.

Rigorous Mathematical Proof via Generating Functions

The fact that the Sicherman distribution perfectly mimics the standard discrete uniform distribution is not a random coincidence discovered through exhaustive computational trial and error; rather, it is an unavoidable, deterministic consequence of polynomial algebra. The definitive proof of the Sicherman dice—and the rigorous verification that they represent the only possible alternative numbering system using positive integers—relies entirely on the application of generating functions.

A generating function in probability theory is a formal power series whose sequential coefficients represent a specific sequence of probabilities or combinatorial frequencies. By translating discrete, physically bounded combinatorial problems into the infinite continuum of algebraic polynomials, mathematicians can utilize standard algebraic operations—such as polynomial factorization, division, and multiplication—to deduce complex probabilistic outcomes that would be computationally intractable to map manually.

Formulating the Foundational Polynomials

To initiate the proof, one must define the generating function of a standard six-sided die. Because each side of a fair die has an equal probability of landing face up, we can encode the value of each face as the exponent $k$ of an arbitrary variable $x$. Therefore, the generating polynomial representing a single standard die is denoted as:

$$P_{standard}(x) = x^1 + x^2 + x^3 + x^4 + x^5 + x^6$$

When two independent random variables (such as two distinct dice) are added together in a physical system, the generating function of their aggregate sum is exactly equivalent to the mathematical product of their individual generating functions. This elegant property occurs because multiplying polynomials naturally dictates the addition of their exponents ($x^A \cdot x^B = x^{A+B}$), precisely mirroring the physical act of summing the dice faces to find a total score. Thus, the overarching distribution of the sum of two standard dice is represented by the following quadratic product:

$$D_{sum}(x) = (x + x^2 + x^3 + x^4 + x^5 + x^6)^2$$

Expanding this product results in a comprehensive polynomial where the specific coefficient of each $x^k$ term unambiguously dictates the exact number of ways to physically roll a sum of $k$:

$$D_{sum}(x) = x^{12} + 2x^{11} + 3x^{10} + 4x^9 + 5x^8 + 6x^7 + 5x^6 + 4x^5 + 3x^4 + 2x^3 + x^2$$

A rudimentary inspection of this expanded polynomial confirms that the sequentially ordered coefficients (1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1) perfectly map to the frequency distribution table defined in the previous section of this analysis.

The Factorization of Cyclotomic Polynomials

To mathematically ascertain if another unique set of dice can produce this identical summation polynomial, it is necessary to deconstruct $D_{sum}(x)$ into its prime, irreducible algebraic components over the field of rational numbers. By factoring the master polynomial into its fundamental building blocks, one can theoretically redistribute these prime factors to construct two new polynomials—representing two entirely new dice—whose ultimate product remains completely unchanged.

The generating function for a single standard die can be factored step-by-step utilizing the principles of cyclotomic polynomials:

  1. Extraction of the Common Factor: The polynomial is fundamentally divisible by $x$.
    $$x^6 + x^5 + x^4 + x^3 + x^2 + x = x(1 + x + x^2 + x^3 + x^4 + x^5)$$
  2. Geometric Series Grouping: The remaining expression $(1 + x + x^2 + x^3 + x^4 + x^5)$ represents a finite geometric series. Through algebraic rearrangement, this sequence can be grouped and factored into $(1 + x^3)(1 + x + x^2)$.
  3. Factoring the Sum of Cubes: The binomial expression $(1 + x^3)$ represents a standard sum of cubes, which is a known algebraic identity that can be further factored into $(1 + x)(1 - x + x^2)$.

Consolidating these steps reveals that the generating function for a single standard die breaks down into four strictly irreducible polynomial factors:
$$P_{standard}(x) = x(1 + x)(1 - x + x^2)(1 + x + x^2)$$

Because the overarching probability system governing the outcome distribution is the product of two standard dice, the total generating function is the square of these irreducible factors:
$$D_{sum}(x) = [x^2] \cdot [(1 + x)^2] \cdot [(1 - x + x^2)^2] \cdot [(1 + x + x^2)^2]$$

Applying Geometric and Physical Constraints

To synthesize the Sicherman dice, these eight total irreducible factors must be meticulously redistributed between two novel polynomial functions, defined as $a(x)$ and $b(x)$, which will serve as the mathematical blueprints for the faces of the two new dice. However, this algebraic redistribution is not arbitrary; it is strictly bounded by logical, real-world physical constraints that must govern any object capable of functioning as a die.

Constraint 1: The Requirement of Positive Integers
A physical die must bear tangible, measurable values; it cannot logically possess a face value of 0, nor can it possess negative numbers or fractions, per the parameters of the puzzle. Therefore, every discrete term within both generating polynomials must possess a strictly positive integer power of $x$. This physical reality mathematically dictates that both $a(x)$ and $b(x)$ must be inherently divisible by $x$, guaranteeing an absence of a constant term (which would denote a face value of 0). Because there are exactly two factors of $x$ present in the master equation, one factor of $x$ must be allocated to $a(x)$ and the remaining factor of $x$ must be allocated to $b(x)$.

Constraint 2: The Six-Face Physical Limit
To maintain functional parity with the original system, each newly synthesized die must physically possess exactly six faces. In the realm of polynomial generating functions, if the independent variable $x$ is evaluated at 1, the resulting arithmetic sum of the coefficients equals the total number of terms (and thereby, the total number of geometric faces). Therefore, the system demands that $a(1) = 6$ and $b(1) = 6$.

To navigate this constraint, one must evaluate the remaining irreducible factors at $x = 1$:

  • The factor $(1 + x)$ evaluated at $x = 1$ resolves to $(1 + 1) = 2$.
  • The factor $(1 - x + x^2)$ evaluated at $x = 1$ resolves to $(1 - 1 + 1^2) = 1$.
  • The factor $(1 + x + x^2)$ evaluated at $x = 1$ resolves to $(1 + 1 + 1^2) = 3$.

To successfully achieve a product of 6 at $x=1$ for both respective polynomials, $a(x)$ and $b(x)$ must each individually receive exactly one factor that evaluates to 2, and exactly one factor that evaluates to 3, because algebraically $2 \times 3 = 6$. Thus, the logical framework dictates that $a(x)$ and $b(x)$ must both equally receive one $(1 + x)$ factor and one $(1 + x + x^2)$ factor.

Constraint 3: The Mandate for a Non-Standard Arrangement
At this advanced stage of the redistribution process, $a(x)$ and $b(x)$ have both been allocated an identical base of factors: $x(1 + x)(1 + x + x^2)$. Inspecting the original master equation reveals that the only factors left unassigned are two identical, repeating factors of $(1 - x + x^2)$.

If one of these final $(1 - x + x^2)$ factors is assigned to $a(x)$ and the other mirror factor is assigned to $b(x)$, the resulting polynomials will be completely identical. This symmetrical allocation merely reconstructs the original puzzle, yielding two standard dice: $a(x) = b(x) = P_{standard}(x)$.

Therefore, to produce an alternative, asymmetric numerical arrangement that still satisfies all previous constraints, both remaining factors of $(1 - x + x^2)$ must be forcefully and concurrently allocated to the exact same die. Without any loss of mathematical generality, let both of these complex factors be assigned to the polynomial $b(x)$.

Synthesizing the Final Probability Vectors

By multiplying out these uniquely constrained and distributed prime factors, the distinct generating functions for the Sicherman dice are finally crystallized from the algebra.

For Die A (which received zero $(1 - x + x^2)$ factors):
$$a(x) = x(1 + x)(1 + x + x^2)$$$$a(x) = x(1 + 2x + 2x^2 + x^3)$$$$a(x) = x^1 + 2x^2 + 2x^3 + x^4$$Interpreting this polynomial back into physical geometry, the specific coefficients and exponents of $a(x)$ reveal the physical faces of the first die: it possesses one face with a 1, two faces with a 2, two faces with a 3, and one face with a 4. The resultant physical object is defined by the set {1, 2, 2, 3, 3, 4}.

For Die B (which absorbed both of the $(1 - x + x^2)$ factors):
$$b(x) = x(1 + x)(1 + x + x^2)(1 - x + x^2)^2$$Because the specific products $(1 + x)(1 - x + x^2) = (1 + x^3)$ and $(1 + x + x^2)(1 - x + x^2) = (1 + x^2 + x^4)$ are known algebraic shortcuts, the complex polynomial simplifies rapidly:
$$b(x) = x(1 + x^3)(1 + x^2 + x^4)$$$$b(x) = x(1 + x^2 + x^3 + x^4 + x^5 + x^7)$$$$b(x) = x^1 + x^3 + x^4 + x^5 + x^6 + x^8$$Translating the exponents of $b(x)$, the physical faces of the second die are revealed: it possesses exactly one face each of 1, 3, 4, 5, 6, and 8. The resultant physical object is defined by the set {1, 3, 4, 5, 6, 8}.

Because the rigid algebraic and geometric constraints detailed above organically force this specific, singular redistribution of prime polynomials, the mathematical proof decisively establishes a profound reality: the Sicherman arrangement is not merely one possible alternative. It is the strictly unique, mutually exclusive, and only mathematically viable alternative for renumbering a pair of six-sided dice with positive integers while flawlessly maintaining a standard uniform distribution.

Thermodynamic Isomorphism: Generating Functions and the Partition Function

While the rigorous proof of the Sicherman dice relies fundamentally on combinatorial mathematics and polynomial algebra, the primary mathematical tool utilized—the generating function—is structurally and behaviorally identical to a core, defining concept in quantum and theoretical physics: the partition function within statistical mechanics.

In both the disciplines of statistical mechanics and information theory, complex systems are uniformly evaluated through the defining lens of entropy, a fundamental quantitative measure characterizing unpredictability, disorder, and macroscopic uncertainty. For a discrete set of observable outcomes, the entropy $S$ is mathematically defined by the Shannon-Gibbs formula $S = -\sum p_n \log p_n$, where the variable $p_n$ signifies the exact probability of a specific microscopic outcome $n$ occurring.

For a fully deterministic process—where a specific outcome is practically certain and no randomness exists—the systemic entropy drops to absolute zero. Conversely, for a fair standard die, where outcomes are distributed evenly, the entropy is uniformly maximized relative to its physical constraints, resulting in an entropy value of $S = -\sum (\frac{1}{6}) \log (\frac{1}{6}) = \log(6)$.

When theorists are tasked with analyzing infinitely more complex thermodynamic systems comprising millions or billions of rapidly and randomly moving particles (such as an expanding gas confined within thermal equilibrium), tracking the exact velocity, trajectory, and position of every single constituent molecule is computationally and physically impossible. Theoretical physicists circumvent this insurmountable limitation by evaluating the macroscopic state of the entire system utilizing overarching probability distributions.

The partition function, standardly denoted by the variable $Z$, serves as the primary analytical engine of statistical mechanics. It rigorously encodes the overarching statistical properties of a physical system operating in thermal equilibrium. The fundamental mathematical architecture of the partition function is essentially a massive sum conducted over all possible discrete energy states $i$. This structure is deeply and heavily analogous to a probability generating polynomial utilized in combinatorics.

Where a discrete probability generating function (such as those used to solve the Sicherman dice) continuously adds subsequent terms of $x^k$ to perfectly represent physical dice outcomes of value $k$, the physical partition function adds sequence terms involving the specific exponential variants of distinct energy values. Crucially, the arithmetic operations governing these functions remain structurally isomorphic. Multiplying the respective partition functions of two independent, uncoupled thermodynamic systems intrinsically adds their localized energy states, functioning identically to how multiplying the polynomials of two distinct dice inevitably adds their numerical face values.

This underlying, seamless structural symmetry dictates that abstract combinatorial puzzles specifically involving polynomial generating functions—such as the factorization of integers, random geometric walks, and specifically the Sicherman dice—possess profound and direct analogical echoes regarding how modern physicists map subatomic energy states, trace radiative thermal equilibrium, and compute quantum statistical fluctuations.

The Origin of the Boltzmann Distribution: The Caltech Resolution

The subtle, deep-rooted mathematical connection bridging abstract combinatorial mathematics with physical statistical mechanics was recently brought into brilliant, unprecedented focus. In groundbreaking research published in 2025, theoretical economists and physicists at the California Institute of Technology successfully utilized the exact mathematical infrastructure underlying the Sicherman dice to prove a foundational, 150-year-old theorem dictating the fundamental nature of randomness within the universe.

The Ubiquity and Vulnerability of the Boltzmann Distribution

The Boltzmann distribution, officially named after the physicist Ludwig Boltzmann who initially formulated the concept in 1868 during his pioneering studies of gases, serves as the indisputable bedrock of modern statistical mechanics. It mathematically and definitively dictates the precise probability that a specific physical system, such as a localized volume of atmospheric gas molecules, will be found existing in a particular microscopic state based primarily on that state's inherent energy and the overall macroscopic temperature of the environment.

For well over a century, scientists and physicists have universally relied on the Boltzmann distribution to rationalize and predict the seemingly unpredictable behavior of massive, chaotic systems. It correctly and flawlessly maps diverse phenomena ranging from the kinetic speed of molecular structures in an ideal gas (known specifically as the Maxwell-Boltzmann distribution) to highly complex, multi-variable thermodynamic interactions. The conceptual approach operates upon a premise structurally identical to rolling a pair of dice: while the specific trajectory of a single individual molecule (or the result of a single isolated dice roll) remains entirely uncertain and unpredictable, aggregating millions of repeated random thermodynamic events reveals a perfectly consistent, mathematically predictable pattern of overarching probabilities.

However, despite its universal application, a glaring epistemological vulnerability persisted at the core of theoretical physics: while empirical evidence proved that the Boltzmann distribution clearly and consistently worked, a rigorous, foundational mathematical proof explaining definitively why it was the exclusive, unique theoretical distribution capable of accurately describing these systems remained historically evasive. Theorists, troubled by the unprovable assertions of the ergodic hypothesis, occasionally questioned whether entirely alternative mathematical frameworks might also validly explain thermodynamics without relying on Boltzmann's initial classical postulates.

Testing the "Independence Axiom" Utilizing Crazy Dice

Researchers Fedor Sandomirskiy and Omer Tamuz sought to definitively characterize the Boltzmann distribution and eliminate this century-old ambiguity. To accomplish this monumental task, they focused heavily on a core, undeniable tenet of physical reality: the mathematical independence of uncoupled systems. In the realm of logical probability and physics, if two isolated systems are completely unrelated and physically separated by vast distances, the specific behavior of one system must not possess any mathematical capacity to affect the probability behavior of the other.

To rigorously test whether hypothetical, alternative theoretical distributions could satisfy this fundamental axiom of independence, the researchers required a mathematical testbed of unparalleled precision. They deduced that polynomial probability frameworks—and specifically, the generating functions of the standard dice compared against the unique polynomials of the Sicherman dice—provided the perfect, flawless algebraic analogy.

Because absolutely every probability distribution (whether based firmly on Boltzmann's 1868 classical formulation or any hypothetical, experimentally competing theory) can be explicitly written as a mathematical function, they can all be translated directly into polynomial form for rigorous comparative testing. As previously established in the combinatorial proof, multiplying the precise generating polynomial of a standard die, denoted as $h(x)$, by itself reliably yields the combined statistical distribution $h(x) \cdot h(x)$. Simultaneously, multiplying the two distinctly factored Sicherman generating polynomials, denoted as $f(x)$ and $g(x)$, unequivocally produces the exact same combined sum distribution $f(x) \cdot g(x)$.

This observed mathematical equality, $h(x) \cdot h(x) = f(x) \cdot g(x)$, is demonstrably not just a clever trick of factoring integers; it robustly captures the very essence of two independent, entirely uncoupled physical systems combining to form mathematically identical macroscopic states.

Tamuz and Sandomirskiy logically reasoned that if a competing, alternative theory of statistical mechanics were truly and physically valid, it must unequivocally uphold the lack of mathematical connection between completely unrelated behaviors across all variables. They therefore systematically subjected all known alternative theoretical formulations to this highly specific polynomial "dice test".

Under the strict mathematical laws uniquely defining the Boltzmann distribution, the required independence of the macro-states produced by both standard and Sicherman polynomial systems holds perfectly true and stable. However, when the researchers processed the complex mathematical constraints of competing theories through the polynomial representations of the crazy dice and standard dice, a massive systemic paradox emerged. Under every single alternative theory, the probability distributions of the aggregate sums generated by the two distinct sets of dice irreversibly diverged, failing to maintain parity.

If an alternative physics theory mathematically indicates that the sum distributions of the standard polynomials and crazy dice polynomials no longer uniquely match, it fundamentally and fatally violates the foundational independence axiom. Translated into a physical analogue, this failure would mandate that simply observing the energy state of one isolated system inexplicably and magically alters the physical probability mechanics of an entirely disconnected, uncoupled system lightyears away. Tamuz colorfully and accurately compared this absurd mathematical failure to the "nonsensical example of soap choices affecting cereal choices".

The Mathematical Singularity of Boltzmann

By systematically identifying, factoring, and generating numerous, highly complex variations of generating functions representing "crazy dice" beyond the original 1977 Sicherman pair, Tamuz and Sandomirskiy exhaustively stress-tested the polynomial relationships mapping to physical systems. Through a process of rigorous, unforgiving algebraic elimination, their research, culminating in the 2025 paper titled "On the origin of the Boltzmann distribution" published in Mathematische Annalen, delivered a definitive, unassailable proof: the Boltzmann distribution is a mathematical singularity.

Their proof demonstrated with absolute certainty that the Boltzmann distribution represents the only existing mathematical framework capable of consistently and flawlessly satisfying the required independence for uncoupled probability systems. If a theorist abandons the Boltzmann framework, the foundational mathematics governing independent variables immediately collapses, inevitably generating paradoxical predictions where supposedly independent, isolated physical states suddenly and impossibly influence one another across a vacuum. The polynomial analysis confirms definitively that Boltzmann’s theory is not merely one functional or convenient way to measure statistical thermodynamics; rather, its specific structure is mathematically mandated by the very nature and logic of independent probability.

Interdisciplinary Ramifications: Bridging Economics and Physics

The epistemological resolution provided by the mathematical paradigm of the Sicherman dice extends far beyond the confines of physical thermodynamics, deeply impacting the fundamental architecture of economic modeling and human decision theory. Sandomirskiy and Tamuz originally approached the Boltzmann problem recognizing that theoretical frameworks possessing the specific "nice property that correctly maintains the lack of connection between the unrelated behaviors" are critically necessary in both statistical physics and advanced microeconomics.

In modern economic theory, specifically regarding consumer choice and market forecasting, the multinomial logit model is heavily and ubiquitously utilized to predict precisely how independent individuals will make choices between various mutually exclusive alternatives (e.g., predicting the choice between different modes of transport, or forecasting the probability of purchasing a specific brand of goods in a saturated market). A core, non-negotiable assumption required for the multinomial logit model to function accurately is the principle known as the "Independence of Irrelevant Alternatives" (IIA). This foundational economic assumption states that a rational person's statistical preference between two options should remain mathematically unchanged even if a third, entirely unrelated option is subsequently introduced into the environment.

Because the underlying mathematics generating the probability of distinct choices in microeconomics flawlessly mirrors the mathematical probability equations of molecular energy states in statistical mechanics, the polynomial dice test applied by Caltech yielded powerful parallel conclusions for the field of economics. By definitively proving that the Boltzmann distribution is the absolute singular physical theory that does not produce paradoxical, non-independent links between uncoupled systems, the researchers simultaneously, mathematically proved that the multinomial logit model is the absolutely exclusive economic framework capable of accurately and rationally predicting independent choices in unrelated situations.

The polynomial representations inherent in the original 1977 Sicherman puzzle demonstrably illustrate that dividing either physical energy states or abstract economic choices into logical partitions requires a strict, unyielding adherence to these specific generative functions. Any deviation or structural alteration results in cascading mathematical failures across the entirety of the systemic models, firmly and permanently tethering the accuracy of modern economic predictive algorithms to the exact same mathematical laws that fundamentally govern atmospheric gas expansion and particle equilibrium.

Conclusion

The decades-long evolution and application of the Sicherman dice paradigm serves as a profound, unprecedented testament to the deeply interconnected architecture of formal combinatorial mathematics, quantum mechanics, and socioeconomic theory. What originally emerged in 1977 as a seemingly isolated recreational puzzle—a clever, albeit esoteric, application of cyclotomic polynomials discovered by a mathematician in Buffalo and popularized through the writings of Martin Gardner—has ultimately been revealed as a structurally vital foundational concept with implications and resonance extending far beyond tabletop logic games and Backgammon probability strategy.

The rigorous, step-by-step algebraic factorization of the dice's polynomial generating functions definitively proves that only one singular, positive-integer configuration can possibly exist that flawlessly mimics the standard discrete uniform probability distributions inherent to cubical dice. Yet, the true gravity and scientific value of this combinatorial discovery lies entirely in its deep structural isomorphism. Because the mathematics of polynomial multiplication precisely and natively models both combinatorial probability addition and thermodynamic energy partition functions, the Sicherman dice inadvertently formulated the exact mathematical mechanism required to stress-test the universe's most fundamental rules regarding random, uncoupled systems.

Through the innovative, cross-disciplinary integration of these complex polynomial frameworks into statistical physics and microeconomics, contemporary researchers have finally settled a 150-year-old epistemological debate regarding the validity of classical theories. The abstract concept of "crazy dice" has furnished the scientific community with the definitive proof that the Boltzmann distribution is not an arbitrary theoretical construct or a historical convenience, but rather the singular, mathematically mandated law capable of sustaining the independence of uncoupled macroscopic phenomena without collapsing into paradox. In accomplishing this, the legacy of the Sicherman dice beautifully and comprehensively illustrates that within the rigorous pursuit of pure mathematics, there are no truly isolated curiosities; every abstraction and polynomial factorization holds the inherent potential to decode the fundamental realities and structural laws of the physical world.

Monday, 20 July 2020

Lucas' Problem of the Married Couples

I've seen this problem before but I thought it interesting to revisit it and look at its historical background. This is Problem 8 in "100 Great Problems of Elementary Mathematics" by Heinrich Dörrie. The problem is stated as follows:
How many ways can \(n\) married couples be seated about a round table in such a manner that there is always one man between two women and none of the men is ever next to his own wife?

This problem appeared (probably for the first time) in 1891 in the Theorie des Nombres of the French mathematician Edouard Lucas (1842-1891), author of the famous work Récréations mathématiques. The English mathematician Rouse Ball has said of this problem, “The solution is far from easy.” The problem has been solved by the Frenchmen M. Laisant and M. C. Moreau and by the Englishman H. M. Taylor. A solution based upon modern viewpoints is to be found in MacMahon’s Combinatory Analysis. The approach adopted here is essentially that of Taylor (The Messenger of Mathematics, 32, 1903).
I spent quite some time, on and off, attempting my own solution before coming up short. It was a useful exercise however, because I explored various approaches and the most promising to me seemed to be one involving Cartesian products, so I got a fair bit of practice in working with these products. Once again I was trying for a brute force approach using SageMathCell to create all possible permutations and then imposing progressive restrictions on these permutations. However, the number of permutations quickly become huge and SageMathCell timed out for \(n=5\) and beyond.


According to WolframMathWorld, a closed form expression for \(n>1\) in terms of a sum due to Touchard (1953) is:$$A_n=\sum_k ^n \frac{2n}{2n-k} \binom{2n-k}{k} (n-k)! \, (-1)^k$$Once the formula is known it's easy enough to execute in SageMathCell. Here is the permalink to the calculation up to \(n=10\). The reason I'm quoting from WolframMathWorld and not the original book is that the explanation runs for several pages. Quite simply, as Rouse Ball put it, "the solution is far from easy". Wikipedia gives a simple, four-term recurrence (here is a permalink to the SageMathCell execution of it): $$ A_n = n \, A_{n-1}+2 \, A_{n-2}-(n-4) \, A_{n-3} - A_{n-4} $$ $$ \text{ with } A_2=0, A_3=1,A_4=2,A_5=13$$Wikipedia refers to this sequence of numbers as the mènage numbers and they form OEIS A000179, shown here for \(n=2 \text{ to } 10\):$$0, 1, 2, 13, 80, 579, 4738, 43387, 439792, ... $$It's clear that the number of arrangements increases at a very rapid rate. For just ten couples, there are almost half a million possibilities. The problem has connections with graph theory, knot theory and even chess (see Rooks Problem) but overall I found the problem rather too daunting and didn't have the patience or motivation to wade through the explanation in the book.

However, I'll quote the basis of the book's explanation:
The wives will then all have to be seated on the even- or odd-numbered chairs. In each of these two cases there are \(n!\) dif­ferent possible seating arrangements, so that there are \(2n!\) different possible seating arrangements for the women alone. We will assume that the women have been seated in one of these arrangements and we will maintain this seating arrangement through­ out the following. The nucleus of the problem then consists of deter­mining the number of possible ways of seating the men between the women.
Let us designate the women in the assumed seating sequence as \(F_1, F_2, ..., F_n \), their respective husbands \(M_1, M_2, ...,M_n\), the couples \( (F_1, M_1), (F_2,M_2),...,\) as \(1,2,...\) and the arrangements in which there are \(n\) married couples as \(n\)-pair arrangements. Let us designate the husbands about whom we have no further information as \(X_1, X_2, ...\).
Let \(F_1X_1F_2X_2,...,F_nX_n,F_{n+1}X_{n+1} \) be an (\(n+1)\)-pair arrangement in which none of the husbands sits beside his own wife. It must be remembered that the arrangement is circular, so that \(X_{n+1}\) is seated between \(F_{n+1}\) and \(F_1\). If we take \(F_{n+1}\) and \(M_{n+1}=X_{\nu}\) out of the arrangement and replace \(X_{\nu} \) with \(X_{n+1}=M_{\mu}\), we obtain the \(n\)-pair arrangement: $$F_1X_1F_2X_2...F_{\nu}M_{\mu}F_{\nu+1}...F_nX_n $$This arrangement can occur in three ways:
  1. No man sits next to his wife (thus \( M_{\mu} \neq M_{\nu},M_{\mu} \neq M_{\nu+1}, X_n \neq M_1\)).
  1. One man sits next to his own wife (namely when \(M_{\mu}=M_{\nu}\) or \(M_{\mu}=M_{\nu+1}\) or else \(X_n=M_1\)).
  1. Two men sit next to their own wives (when \(M_{\mu}=M_{\nu}\) or \(M_{\mu}=M_{\nu+1}\) and at the same time \(X_n=M_1\), that is, when in our arrangement the order \(M_1F_1\) occurs.
It goes on and on from there but that's the start of the explanation anyway. On looking further ahead in the book, it seems that in general the problems are rather too difficult for a recreational mathematician to approach. For that reason, I may go back to Project Euler of which I've solved only 8 out of the 723 available problems. These problems are mathematical and require a programming solution.

Saturday, 20 June 2020

Prouhet-Thue-Morse Sequence

I was reminded of this sequence when I rewatched a Numberphile YouTube video that related the sequence to the game of chess.


The Prouhet-Thue-Morse is a simple enough sequence but one with many practical applications. It can be described using formal mathematical notation but it can be described in so-called layman's terms as well. This gif from Wikipedia is an example of the latter:


A close look at this gif and it's clear enough how the sequence is being constructed. My last two posts have focussed on recurrence relations and the Prouhet-Thue-Morse sequence can be described more formally as a recurrence relation:$$ \begin{align} t_0 &= 0\\ t_{2n} &= t_n\\ t_{2n+1} &= 1 - t_n \end{align}$$wikiHow has a variety of algorithms for creating the sequence. One uses the recurrence relation as shown in Figure 1:

Figure 1

I incorporated this approach into SageMathCell as shown in Figure 2 (permalink):

Figure 2: permalink

Another approach, what wikiHow calls the Direct Definition, uses the binary form of the natural (decimal) numbers, calculates their binary sum and then uses the modulus 2 of this sum as the output. What's happening is that decimal numbers with an even number of 1's in their binary form are assigned a ZERO and those with an odd number of 1's are assigned a ONE.

\(t_0 = 0 \text{ and } t_n \equiv s_n \bmod{2} \text{ where }s_n \text{ is the binary sum of }n\)

This algorithm is even easier to implement in SageMathCell. See Figure 3 where the output is shown, for variety, as a string rather than a list of elements (permalink):

Figure 2: permalink

The following is an excellent video that I came across from a mathematician who, unconsciously, used the Thue-Morse sequence (sometimes the Prouhet part of the name is omitted) as a child to cope with his obsessive compulsive disorder. Later he describes how he unwittingly used the sequence to solve the Mathematics problem described in Figure 3:

Figure 3



Of course the sequence can be represented with elements other than 0's and 1's. For example, suppose that two persons want to divide an even number of items of equal value between themselves. If the choosing sequence goes ABABABAB ... or BABABABA ... then the person choosing second will always be behind 50% of the time in terms of what they've accumulated. However, using the Thus-Morse sequence, the lead will alternate and in fact represents the fairest way to share things:

ABBABAABBAABABBABAABABBAABBABAABBAABABBAABBABAABABB

Finally, here is a video on the sequence that Stand-up Maths did some years ago:

Wednesday, 7 August 2019

Lines and Triangles

Consider the following problem as shown in Figure 1.


Figure 1

I just stumbled upon this problem, or rather a generalisation of this problem, and thought its solution was worthy of a mention. The solution was quite simple once I read it. Let's first review what the diagram shows. There are three parallel lines (labelled 1, 2 and 3) and another five non-parallel lines (labelled 4 to 8) that intersect with each other and also with the parallel lines. No three lines pass through a single point. How many triangles are formed?

Let's break the problem into two parts. Firstly let's deal with the five non-parallel lines. It takes three lines to make a triangle and so there are$$ \binom 5 3 = \binom 5 2 =\frac{5 \times 4}{2 \times 1}= 10 \text { possible combinations}$$So the five non-parallel lines form 10 triangles with each other. The three parallel lines can each be linked to a pair of non-parallel lines. This becomes:$$ \binom 5 2 \times 3 = 10 \times 3 = 30 \text{ possible combinations}$$So in total there are \(10 + 30 = 40\) triangles formed.

Generalising this, if there are \( n \) non-parallel lines and \(m\) parallel lines then:$$\text {The number of triangles formed is given by } \binom n 3 + \binom n 2 \times m$$Of course if none of the lines are parallel then \(m=0\) and the expression simplifies accordingly. It's interesting to count the number of points as well (shown in Figure 2):


Figure 2

The intersection of the lines produces 25 points, which I dutifully counted and labelled. If the points are taken in pairs, then each pair will generate a line with the result that there will be \( \binom {25} 2 = \frac {25 \times 24}{2 \times 1}=300\) lines which is clearly not the case because many of the lines are the same as others due to the large number of collinear points. 

However it can be noted that when two lines intersect, a point is created and so the following expression arises:$$ \binom 5 2 + 5 \times 3 = 10 + 15 =25 \text { which confirms my manual count}$$This can be generalised to:$$ \text {The number of points is given by }\binom n 2 + n \times m$$

Sunday, 13 January 2019

Derangements

Today I turned 25487 days old and the first OEIS entry for this number is A002467
Given \(n\) letters and \(n\) envelopes, how many ways are there to fill the envelopes so that at least one letter goes into its right envelope? 
It took some further investigation to realise that this sequence was closely related to OEIS A000166 the numbers of derangements of \(n\): 1, 0, 1, 2, 9, 44, 265, 1854, 14833, 133496, 1334961, 14684570, 176214841, 2290792932, ...

So what is a derangement? According to Wikipedia:
In combinatorial mathematics, a derangement is a permutation of the elements of a set, such that no element appears in its original position. In other words, derangement is a permutation that has no fixed points. 
The number of derangements of a set of size \(n\), usually written \(Dn\), \(dn\), or \(!n\), is called the "derangement number" or "de Montmort number". (These numbers are generalised to rencontres numbers.) The subfactorial function (not to be confused with the factorial \(n!\)) maps \(n\) to \(!n\). No standard notation for subfactorials is agreed upon; \(n¡\) is sometimes used instead of \(!n\). 
The problem of counting derangements was first considered by Pierre Raymond de Montmort in 1708; he solved it in 1713, as did Nicholas Bernoulli at about the same time.
To construct the formula, let's consider \(n\) letters and \(n\) envelopes. The first envelope can be filled in \(n-1\) ways and, for the second envelope, there are two possibilities. If the second envelope is filled with the first letter, then the first and second letters are taken care of the problem is reduced to \(n-2\) envelopes and \(n-2\) letters. If this does not happen, then there are now \(n-1\) envelopes and \(n-1 \) letters. This can be written as: $$ !n=(n-1)(!(n-1)+!(n-2))$$From here a formula can be derived to calculate the derangements for \(n\) items, specifically:$$!n=n! \sum_{i=0}^{n} \frac{(-1)^n}{i!}$$For this formula !0=1 and !1=0. In the case of 8 letters and 8 envelopes, we get: !8 = 14833.

One letter has ended up in the right envelope. There are 25487
ways in which at least one letter will end up in the right envelope.

So 14833 is the number of ways that no letters end up in the right envelopes. We are interested in the number of ways that at least one letter will end up in the right envelope. So 14833 needs to be subtracted from 8! = 40320 (the total number of possibilities) to get 25487.

Let's look at how the probability of a derangement changes as the number of elements increases. It can be noted that the Taylor Series for the function \(f(x)=1/e^x\) is given by:$$
\frac{1}{e^x}= \sum_{i=0}^{\infty} \frac{(-1)^i x^i}{i!}
$$So when \(x=1\), it can be seen that \(1/e\) is identical to the formula for the derangements:$$
\frac{1}{e}= \sum_{i=0}^{\infty} \frac{(-1)^i}{i!} \approx 0.3678794412
$$So after about four elements, the probability of a derangement quickly settles down to about 37%, no matter what the number of elements. Here is a link to a paper on derangements that begins:
A group of \(n\) men enter a restaurant and check their hats. The hat-checker is absent minded, and upon leaving, she redistributes the hats back to the men at random. What is the probability \(P_n\) that no man gets his correct hat, and how does \(P_n\) behave as \(n \rightarrow \infty\)?
Here are two Numberphile videos on Derangements with James Grimes presenting. The first is an introduction and the second derives a proof for the formula:



Wednesday, 9 May 2018

Necklaces and Bracelets

At my recent diurnal age of 25136 (I'm 25138 days old as I write this), I noted that:
25236 is also a member of OEIS A141783: number of bracelets (turn over necklaces) with n beads: 1 blue, 12 green, and r = n-13 red (here n=20 and so r=7). This can be restated as "the number of bracelets with 1 blue, 12 green and 7 red beads is 25236". 
I had trouble understanding why the number of bracelets was 25236 and not 25194. According to my initial calculations, the number of necklaces (arrangements of beads that can't be lifted out of the plane and reversed) should be 19!/(12!*7!) = 50388. Here the numerator is 19! because 20!/20 adjusts for the rotational symmetry of the twenty beads and the denominator takes into account the fact that the beads in each of the groups, 12 green and 7 red, are indistinguishable from one another. Because bracelets can be lifted out of the plane and turned over, the number of bracelets should be 50338/2 = 25194.

As with most things, it's better to start at the beginning. The sequence runs: 1, 7, 49, 231, 924, 3108, 9324, 25236, ... and begins with n=13 at which point there is only one possible configuration as there are no red beads. When n=14, there is one red bead, one blue bead and twelve green beads. I would reckon the number of possible necklace configurations to be: 13!/12!=13 but in fact there is one more as can be seen in Diagram 1 and 2:

Diagram 1: blue bead on left, red bead on right

Diagram 2: red bead on left, blue bead on right.

As the two diagrams show, the first configuration with a blue bead on the left and a red bead on the right can be rotated to produce a new configuration where the red bead is on the left and the blue bed is on the right. This means that there are 13+1=14 possible necklaces and thus 14/2=7 possible bracelets.

When there are 20 beads, the situation is of course more complicated but the principle is the same. There will be the 50388 necklaces as calculated above but there are also the extra necklaces created by rotating the blue and red beads by 180° for the symmetric configurations like the one shown in Diagram 3. In every symmetric configuration, there will be nine beads (six green and three red) on either side of the red-blue bead axis. There are \( \binom{9}{3} = 84 \) ways this can be done and so the total number of necklaces is 50388+84=50472, corresponding to 50472/2=25236 bracelets.
Diagram 3: a symmetrical position with green and red
identically placed on either side of the red-blue axis


Saturday, 7 April 2018

The New Powerball

I received an email from the Lott today announcing the following changes to Powerball:
New Powerball Updates 
BIG JACKPOTS
There is an increased chance of big jackpots occurring more often.
 
MORE WINNERS
There will be more overall winners in every draw with the chance of winning an overall prize increasing from 1 in 78 to 1 in 44.
 
NEW 9TH PRIZE DIVISION
The Powerball prize structure will include an extra 9th prize division.
 
NUMBER UPDATES
The New Powerball game will feature 7 winning numbers drawn from a barrel of 35 balls (numbered 1-35). This was previously 6 numbers drawn from a barrel of 40 balls (numbered 1-40).
 
We’ve randomly generated replacements for numbers greater than 35 and added a new 7th number to your Favourite and Subscription entries.
There will be no changes to the Powerball. It will still be drawn from a barrel of 20 balls (numbered 1-20).
This claim of an increased chance of big jackpots occurring more often is perplexing because it seems that the number of possible combinations has increased, meaning the probability of winning has decreased (significantly as we can see below):$$ \text{BEFORE }\binom{40}{6} \times 20 = 76,767,600 \text{ <---> AFTER } \binom{35}{7} \times 20 = 134,490,400$$ The chance of winning, that is getting the correct combination of seven numbers and the powerball, is now almost halved.

Maybe I'm missing something but I can't see what it is. There may well be more overall winners with the introduction of a 9th prize division but I wonder if the provision of even more piddling minor prizes will actually entice punters. Even without knowing the precise probability, most punters will recognise intuitively that, with the powerball choices remaining the same, the chance of getting seven numbers correct out of 35 is going to be considerably less than getting six numbers out of 40. All punters have their eye of the big prize not on the increasing proliferation of minor prizes.