In last week’s post, we defined an extension of parity from the integers to the rational numbers. Three parity classes were found — even, odd and *none*. This week, we show that, with an appropriate ordering or enumeration of the rationals, the three classes are not only equinumerate (having the same cardinality) but of equal density in . This article is a condensation of part of a paper [Lynch & Mackey, 2022] recently posted on arXiv.

## Posts Tagged 'Number Theory'

### Parity and Partition of the Rational Numbers. Part II: Density of the Three Parity Classes

Published May 12, 2022 Occasional Leave a CommentTags: Number Theory

### Parity and Partition of the Rational Numbers. Part I: The Three Parity Classes

Published May 5, 2022 Occasional Leave a CommentTags: Number Theory

We define an extension of parity from the integers to the rational numbers. Three parity classes are found — even, odd and *none*. Using the 2-adic valuation, we partition the rationals into subgroups with a rich algebraic structure.

Continue reading ‘Parity and Partition of the Rational Numbers. Part I: The Three Parity Classes’

We are all familiar with splitting natural numbers into prime components. This decomposition is unique, except for the order of the factors. We can apply the idea of prime components to many more general sets of numbers.

The **Gaussian integers** are all the complex numbers with integer real and imaginary parts, that is, all numbers in the set

The set forms a two-dimensional lattice in the complex plane. For any element we consider the four numbers as *associates*. The associates of are known as units: .

### Number Partitions: Euler’s Astonishing Insight

Published December 23, 2021 Occasional Leave a CommentTags: Euler, Number Theory

In 1740, French mathematician Philippe Naudé wrote to Leonhard Euler asking in how many ways a positive integer can be written as a sum of distinct numbers. In his investigations of this, Euler established the theory of partitions, for which he used the term *partitio numerorum.*

Many of Euler’s results in number theory involved divergent series. He was courageous in manipulating these but had remarkable insight and, almost invariably, his findings, although not rigorously established, were valid.

** Partitions**

In number theory, a *partition* of a positive integer is a way of writing as a sum of positive integers. The order of the summands is ignored: two sums that differ only in their order are considered the same partition.

Continue reading ‘Number Partitions: Euler’s Astonishing Insight’

### Set Density: are even numbers more numerous than odd ones?

Published December 9, 2021 Occasional Leave a CommentTags: Number Theory

In pure set-theoretic terms, the set of even positive numbers is the same size, or cardinality, as the set of all natural numbers: both are infinite countable sets that can be put in one-to-one correspondence through the mapping . This was known to Galileo. However, with the usual ordering,

every second number is even and, intuitively, we feel that there are half as many even numbers as natural numbers. In particular, our intuition tells us that** if is a proper subset of , it must be smaller than .**

Continue reading ‘Set Density: are even numbers more numerous than odd ones?’

### A Grand Unification of Mathematics

Published October 7, 2021 Irish Times Leave a CommentTags: Algebra, Analysis, Group Theory, Number Theory

There are numerous branches of mathematics, from arithmetic, geometry and algebra at an elementary level to more advanced fields like number theory, topology and complex analysis. Each branch has its own distinct set of axioms, or fundamental assumptions, from which theorems are derived by logical processes. While each branch has its own flavour, character and methods, there are also strong overlaps and interdependencies. Several attempts have been made to construct a grand unified theory that embraces the entire field of maths [TM220 or search for “thatsmaths” at irishtimes.com].

### The Spine of Pascal’s Triangle

Published September 30, 2021 Occasional Leave a CommentTags: Arithmetic, Number Theory

We are all familiar with Pascal’s Triangle, also known as the Arithmetic Triangle (AT). Each entry in the AT is the sum of the two closest entries in the row above it. The -th entry in row is the binomial coefficient (read -choose-), the number of ways of selecting elements from a set of distinct elements.

### All Numbers Great and Small

Published July 15, 2021 Irish Times Leave a CommentTags: Number Theory, Physics

Is space continuous or discrete? Is it smooth, without gaps or discontinuities, or granular with a limit on how small a distance can be? What about time? Can time be repeatedly divided into smaller periods without any limit, or is there a shortest interval of time? We don’t know the answers. There is much we do not know about physical reality: is the universe finite or infinite? Are space and time arbitrarily divisible? Does our number system represent physical space and time? [TM215 or search for “thatsmaths” at irishtimes.com]. Continue reading ‘All Numbers Great and Small’

### The Simple Arithmetic Triangle is full of Surprises

Published June 3, 2021 Irish Times Leave a CommentTags: Arithmetic, Number Theory

Pascal’s triangle is one of the most famous of all mathematical diagrams, simple to construct and yet rich in mathematical patterns. These can be found by a web search, but their discovery by study of the diagram is vastly more satisfying, and there is always a chance of finding something never seen before [TM212 or search for “thatsmaths” at irishtimes.com].

Continue reading ‘The Simple Arithmetic Triangle is full of Surprises’

### Goldbach’s Conjecture: if it’s Unprovable, it must be True

Published March 4, 2021 Irish Times 1 CommentTags: Euler, Logic, Number Theory

The starting point for rigorous reasoning in maths is a system of axioms. An axiom is a statement that is assumed, without demonstration, to be true. The Greek mathematician Thales is credited with introducing the axiomatic method, in which each statement is deduced either from axioms or from previously proven statements, using the laws of logic. The axiomatic method has dominated mathematics ever since [TM206 or search for “thatsmaths” at irishtimes.com].

Continue reading ‘Goldbach’s Conjecture: if it’s Unprovable, it must be True’

### Derangements and Continued Fractions for e

Published December 31, 2020 Occasional Leave a CommentTags: Combinatorics, Number Theory

We show in this post that an elegant continued fraction for can be found using derangement numbers. Recall from last week’s post that we call any permutation of the elements of a set an *arrangement*. A *derangement* is an arrangement for which every element is moved from its original position.

Continue reading ‘Derangements and Continued Fractions for e’

### Arrangements and Derangements

Published December 24, 2020 Irish Times Leave a CommentTags: Combinatorics, Number Theory

Six students entering an examination hall place their cell-phones in a box. After the exam, they each grab a phone at random as they rush out. What is the likelihood that none of them gets their own phone? The surprising answer — about 37% whatever the number of students — emerges from the theory of derangements.

### Will RH be Proved by a Physicist?

Published December 10, 2020 Occasional Leave a CommentTags: Analysis, Number Theory

The Riemann Hypothesis (RH) states that all the non-trivial (non-real) zeros of the zeta function lie on a line, the *critical line*, . By a simple change of variable, we can have them lying on the real axis. But the eigenvalues of any hermitian matrix are real. This led to the *Hilbert-Polya Conjecture*:

The non-trivial zeros of are the

eigenvalues of a hermitian operator.

Is there a *Riemann operator*? What could this operater be? What dynamical system would it represent? Are prime numbers and quantum mechanics linked? Will RH be proved by a physicist?

This last question might make a purest-of-the-pure number theorist squirm. But it is salutary to recall that, of the nine papers that Riemann published during his lifetime, four were on physics!

### The p-Adic Numbers (Part 2)

Published October 29, 2020 Occasional Leave a CommentTags: Number Theory

Kurt Hensel, born in Königsberg, studied mathematics in Berlin and Bonn, under Kronecker and Weierstrass; Leopold Kronecker was his doctoral supervisor. In 1901, Hensel was appointed to a full professorship at the University of Marburg. He spent the rest of his career there, retiring in 1930.

Hensel is best known for his introduction of the *p*-adic numbers. They evoked little interest at first but later became increasingly important in number theory and other fields. Today, *p*-adics are considered by number theorists as being “just as good as the real numbers”. Hensel’s *p*-adics were first described in 1897, and much more completely in his books, *Theorie der algebraischen Zahlen*, published in 1908 and *Zahlentheorie* published in 1913.

### The p-Adic Numbers (Part I)

Published October 22, 2020 Occasional Leave a CommentTags: Number Theory

The motto of the Pythagoreans was “All is Number”. They saw numbers as the essence and foundation of the physical universe. For them, numbers meant the positive whole numbers, or natural numbers , and ratios of these, the positive rational numbers . It came as a great shock that the diagonal of a unit square could not be expressed as a rational number.

If we arrange the rational numbers on a line, there are gaps everywhere. We can fill these gaps by introducing additional numbers, which are the limits of sequences of rational numbers. This process of *completion* gives us the real numbers , which include rationals, irrationals like and transcendental numbers like .

### Think of a Number: What are the Odds that it is Even?

Published August 13, 2020 Occasional Leave a CommentTags: Number Theory, Probability

Pick a positive integer at random. What is the chance of it being 100? What or the odds that it is even? What is the likelihood that it is prime?

Continue reading ‘Think of a Number: What are the Odds that it is Even?’

### The Ever-growing Goals of Googology

Published July 2, 2020 Irish Times Leave a CommentTags: Arithmetic, Number Theory

In 1920, a kindergarten class was asked to describe the biggest number that they could imagine. One child proposed to “write down digits until you get tired”. A more concrete idea was to write a one followed by 100 zeros. This number, which scientists would express as ten to the power 100, was given the name “googol” by its inventor [TM190; or search for “thatsmaths” at irishtimes.com ].

### The Online Encyclopedia of Integer Sequences

Published June 25, 2020 Occasional Leave a CommentTags: Analysis, Arithmetic, Number Theory

Suppose that, in the course of an investigation, you stumble upon a string of whole numbers. You are convinced that there must be a pattern, but you cannot find it. All you have to do is to type the string into a database called OEIS — or simply “Slone’s” — and, if the string is recognized, an entire infinite sequence is revealed. If the string belongs to several sequences, several choices are offered. OEIS is a great boon to both professional mathematicians and applied scientists in fields like physics, chemistry, astronomy and biology.

Continue reading ‘The Online Encyclopedia of Integer Sequences’

### John Horton Conway: a Charismatic Genius

Published April 23, 2020 Occasional Leave a CommentTags: Games, Group Theory, Number Theory, Recreational Maths, Topology

John Horton Conway was a charismatic character, something of a performer, always entertaining his fellow-mathematicians with clever magic tricks, memory feats and brilliant mathematics. A Liverpudlian, interested from early childhood in mathematics, he studied at Gonville & Caius College in Cambridge, earning a BA in 1959. He obtained his PhD five years later, after which he was appointed Lecturer in Pure Mathematics.

In 1986, Conway moved to Princeton University, where he was Professor of Mathematics and John Von Neumann Professor in Applied and Computational Mathematics. He was awarded numerous honours during his career. Conway enjoyed emeritus status from 2013 until his death just two weeks ago on 11 April.

### Bang! Bang! Bang! Explosively Large Numbers

Published March 26, 2020 Occasional Leave a CommentTags: Algebra, Number Theory

which is approximately . The number of atoms in the universe is estimated to be about . When we consider permutations of large sets, even more breadth-taking numbers emerge.

Continue reading ‘Bang! Bang! Bang! Explosively Large Numbers’

### The “extraordinary talent and superior genius” of Sophie Germain

Published January 16, 2020 Irish Times Leave a CommentTags: History, Mechanics, Number Theory

When a guitar string is plucked, we don’t see waves travelling along the string. This is because the ends are fixed. Instead, we see a standing-wave pattern. Standing waves are also found on drum-heads and on the sound-boxes of violins. The shape of a violin strongly affects the quality and purity of the sound, as it determines the mixture of standing wave harmonics that it can sustain [TM179 or search for “thatsmaths” at irishtimes.com].

Continue reading ‘The “extraordinary talent and superior genius” of Sophie Germain’

### Spiralling Primes

Published September 12, 2019 Occasional 1 CommentTags: Number Theory, Recreational Maths

The prime numbers have presented mathematicians with some of their most challenging problems. They continue to play a central role in number theory, and many key questions remain unsolved.

** Order and Chaos **

The primes have many intriguing properties. In his article “The first 50 million prime numbers”, Don Zagier noted two contradictory characteristics of the distribution of prime numbers. The first is the erratic and seemingly chaotic way in which the primes “grow like weeds among the natural numbers”. The second is that, when they are viewed in the large, they exhibit “stunning regularity”.

### Closing the Gap between Prime Numbers

Published April 18, 2019 Irish Times Leave a CommentTags: Arithmetic, Number Theory

Occasionally, a major mathematical discovery comes from an individual working in isolation, and this gives rise to great surprise. Such an advance was announced by Yitang Zhang six years ago. [TM161 or search for “thatsmaths” at irishtimes.com].

### Massive Collaboration in Maths: the Polymath Project

Published April 11, 2019 Occasional Leave a CommentTags: Number Theory

Sometimes proofs of long-outstanding problems emerge without prior warning. In the 1990s, Andrew Wiles proved Fermat’s Last Theorem. More recently, Yitang Zhang announced a key result on bounded gaps in the prime numbers. Both Wiles and Zhang had worked for years in isolation, keeping abreast of developments but carrying out intensive research programs unaided by others. This ensured that they did not have to share the glory of discovery, but it may not be an optimal way of making progress in mathematics.

**Polymath**

**Is massively collaborative mathematics possible?** This was the question posed in a 2009 blog post by Timothy Gowers, a Cambridge mathematician and Fields Medal winner. Gowers suggested completely new ways in which mathematicians might work together to accelerate progress in solving some really difficult problems in maths. He envisaged a forum for the online discussion of problems. Anybody interested could contribute to the discussion. Contributions would be short, and could include false routes and failures; these are normally hidden from view so that different workers repeat the same mistakes.

Continue reading ‘Massive Collaboration in Maths: the Polymath Project’

### Multiple Discoveries of the Thue-Morse Sequence

Published February 21, 2019 Irish Times Leave a CommentTags: Algorithms, Number Theory

It is common practice in science to name important advances after the first discoverer or inventor. However, this process often goes awry. A humorous principle called Stigler’s Law holds that no scientific result is named after its original discoverer. This law was formulated by Professor Stephen Stigler of the University of Chicago in his publication “Stigler’s law of eponymy”. He pointed out that his “law” had been proposed by others before him so it was, in a sense, self-verifying. [TM157 or search for “thatsmaths” at irishtimes.com].

Continue reading ‘Multiple Discoveries of the Thue-Morse Sequence’### Really, 0.999999… is equal to 1. Surreally, this is not so!

Published January 10, 2019 Occasional Leave a CommentTags: Analysis, Number Theory

The value of the recurring decimal 0.999999 … is a popular topic of conversation amongst amateur mathematicians of various levels of knowledge and expertise. Some of the discussions on the web are of little value or interest, but the topic touches on several subtle and deep aspects of number theory.

Continue reading ‘Really, 0.999999… is equal to 1. Surreally, this is not so!’

### Random Numbers Plucked from the Atmosphere

Published December 6, 2018 Irish Times Leave a CommentTags: Number Theory

Randomness is a slippery concept, defying precise definition. A simple example of a random series is provided by repeatedly tossing a coin. Assigning “1” for heads and “0” for tails, we generate a random sequence of binary digits or *bits*. Ten tosses might produce a sequence such as 1001110100. Continuing thus, we can generate a sequence of any length having no discernible pattern [TM152 or search for “thatsmaths” at irishtimes.com].

Continue reading ‘Random Numbers Plucked from the Atmosphere’

### Listing the Rational Numbers III: The Calkin-Wilf Tree

Published November 8, 2018 Occasional Leave a CommentTags: Arithmetic, Number Theory

The rational numbers are countable: they can be put into one-to-one correspondence with the natural numbers. In previous articles we showed how the rationals can be presented as a list that includes each rational precisely once. One approach leads to the Farey Sequences. A second, related, approach gives us the Stern-Brocot Tree. Here, we introduce another tree structure, The Calkin-Wilf Tree.

Continue reading ‘Listing the Rational Numbers III: The Calkin-Wilf Tree’

### Listing the Rational Numbers II: The Stern-Brocot Tree

Published October 11, 2018 Occasional Leave a CommentTags: Arithmetic, Number Theory

The rational numbers are countable: they can be put into one-to-one correspondence with the natural numbers. But it is not obvious how to construct a list that is sure to contain every rational number precisely once. In a previous post we described the Farey Sequences. Here we examine another, related, approach.

Continue reading ‘Listing the Rational Numbers II: The Stern-Brocot Tree’

### Listing the Rational Numbers: I. Farey Sequences

Published September 27, 2018 Occasional Leave a CommentTags: Arithmetic, Number Theory

We know, thanks to Georg Cantor, that the rational numbers — ratios of integers — are countable: they can be put into one-to-one correspondence with the natural numbers.

Continue reading ‘Listing the Rational Numbers: I. Farey Sequences’

Godfrey Harold Hardy’s memoir, *A Mathematician’s Apology*, was published when he was 63 years old. It is a slight volume at just 90 pages, but is replete with interesting observations and not a few controversial opinions. After 78 years, it is still in print and is available in virtually every mathematics library. Though many of Hardy’s opinions are difficult to support and some of his predictions have turned out to be utterly wrong, the book is still well worth reading.

### Kaprekar’s Number 6174

Published January 25, 2018 Occasional 1 CommentTags: Number Theory, Recreational Maths

The Indian mathematician D. R. Kaprekar spent many happy hours during his youth solving mathematical puzzles. He graduated from Fergusson College in Pune in 1929 and became a mathematical teacher at a school in Devlali, north-east of Mumbai.

### More on Moduli

Published November 6, 2017 Occasional Leave a CommentTags: Arithmetic, Number Theory

We wrote last week on *modular arithmetic*, the arithmetic of remainders. Here we will examine a few other aspects of this huge subject. Modular arithmetic was advanced by Gauss in his *Disquisitiones Arithmeticae*. In this system, number wrap around when they reach a point known as the modulus. Numbers that differ by a multiple of the modulus are called congruent. Thus 4, 11 and 18 are all congruent modulo 7.

### Fractions of Fractions of Fractions

Published August 10, 2017 Occasional 1 CommentTags: Arithmetic, Number Theory, Recreational Maths

Numbers can be expressed in several different ways. We are familiar with whole numbers, fractions and decimals. But there is a wide range of other forms, and we examine one of them in this article. Every rational number can be expanded as a continued fraction:

where all are integers, all positive except perhaps . If we add it to ; then the expansion is unique.

### It’s as Easy as Pi

Published August 3, 2017 Irish Times Leave a CommentTags: Archimedes, Geometry, Number Theory, Pi

Every circle has the property that the distance around it is just over three times the distance across. This has been known since the earliest times [see TM120 or search for “thatsmaths” at irishtimes.com].

The constant ratio of the circumference to the diameter, denoted by the Greek letter pi, is familiar to every school-child. You might expect to find a proof in Euclid’s *Elements of Geometry*, he could not prove it, and he made no mention of the ratio (see last week’s post).

### A Remarkable Pair of Sequences

Published June 8, 2017 Occasional Leave a CommentTags: Number Theory

The terms of the two integer sequences below are equal for all such that , but equality is violated for this enormous value and, intermittently, for larger values of .

### A Geometric Sieve for the Prime Numbers

Published April 27, 2017 Occasional Leave a CommentTags: Number Theory, Primes

In the time before computers (BC) various ingenious devices were invented for aiding the extensive calculations required in astronomy, navigation and commerce. In addition to calculators and logarithms, several *nomograms* were devised for specific applications, for example in meteorology and surveying.

### Numerical Coincidences

Published March 23, 2017 Occasional Leave a CommentTags: Number Theory, Recreational Maths

A numerical coincidence is an equality or near-equality between different mathematical quantities which has no known theoretical explanation. Sometimes such equalities remain mysterious and intriguing, and sometimes theory advances to the point where they can be explained and are no longer regarded as surprising.

### Brun’s Constant and the Pentium Bug

Published March 9, 2017 Occasional 1 CommentTags: Arithmetic, Euler, Number Theory

Euclid showed by a deliciously simple argument that the number of primes is infinite. In a completely different manner, Euler confirmed the same result. Euler’s conclusion followed from his demonstration that the sum of the reciprocals of the primes diverges:

Obviously, this could not happen if there were only finitely many primes.

### The Shaky Foundations of Mathematics

Published December 1, 2016 Irish Times Leave a CommentTags: Algorithms, Logic, Number Theory

The claim is often made that mathematical results are immutable. Once proven, they remain forever valid. But things are not so simple. There are problems at the very core of mathematics that cast a shadow of uncertainty. We can never be absolutely sure that the foundations of our subject are rock-solid [TM104 or search for “thatsmaths” at irishtimes.com].

The ancient Greeks put geometry on a firm footing. Euclid set down a list of axioms, or basic intuitive assumptions. Upon these, the entire edifice of Euclidean geometry is constructed. This axiomatic approach has been the model for mathematics ever since.

Every number is interesting. Suppose there were uninteresting numbers. Then there would be a smallest one. But this is an interesting property, contradicting the supposition. By *reductio ad absurdum*, there are none!

This is the hundredth “That’s Maths” article to appear in *The Irish Times* [TM100, or search for “thatsmaths” at irishtimes.com]. To celebrate the event, we have composed an ode to the number 100.

The counting numbers that we learn as children are so familiar that using them is second nature. They bear the appropriate name **natural numbers**. From then on, names of numbers become less and less apposite.

### Random Harmonic Series

Published July 28, 2016 Occasional Leave a CommentTags: Analysis, Number Theory, Probability

We consider the convergence of the random harmonic series

where is chosen randomly with probability of being either plus one or minus one. It follows from the Kolmogorov three-series theorem that the series is “almost surely” convergent.

### Lecture sans paroles: the factors of M67

Published June 30, 2016 Occasional Leave a CommentTags: Number Theory

In 1903 Frank Nelson Cole delivered an extraordinary lecture to the American Mathematical Society. For almost an hour he performed a calculation on the chalkboard without uttering a single word. When he finished, the audience broke into enthusiastic applause.

The prime numbers have challenged and perplexed the greatest mathematicians for millennia. Shortly before he died, the brilliant Hungarian number theorist Paul Erdös said “it will be another million years, at least, before we understand the primes”.

### Andrew Wiles wins 2016 Abel Prize

Published May 19, 2016 Irish Times Leave a CommentTags: Algebra, Number Theory

A recent post described the Abel Prize, effectively the Nobel Prize for Mathematics, and promised a further post when the 2016 winner was announced. This is the follow-up post [also at TM091, or search for “thatsmaths” at irishtimes.com].

Next Tuesday, HRH Crown Prince Haakon will present the Abel Medal to Sir Andrew Wiles at a ceremony in Oslo. The Abel Prize, comparable to a Nobel Prize, is awarded for outstanding work in mathematics. Wiles has won the award for his “stunning proof of Fermat’s Last Theorem” with his research “opening a new era in number theory”. Wiles’ proof made international headlines in 1994 when he cracked one of the most famous and long-standing unsolved problems in mathematics.

Pierre de Fermat, a French lawyer and amateur mathematician, stated the theorem in 1637, writing in the margin of a maths book that he had “a truly marvellous proof”. But for more than 350 years no proof was found despite the efforts of many of the most brilliant mathematicians.

### Ramanujan’s Astonishing Knowledge of 1729

Published May 12, 2016 Occasional 1 CommentTags: Number Theory, Ramanujan

**Question:** What is the connection between Ramanujan’s number 1729 and Fermat’s Last Theorem? For the answer, read on.

The story of how Srinivasa Ramanujan responded to G. H. Hardy’s comment on the number of a taxi is familiar to all mathematicians. With the recent appearance of the film *The Man who Knew Infinity*, this curious incident is now more widely known.

Visiting Ramanujan in hospital, Hardy remarked that the number of the taxi he had taken was 1729, which he thought to be rather dull. Ramanujan replied “No, it is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways.”

Continue reading ‘Ramanujan’s Astonishing Knowledge of 1729′

### Prime Number Record Smashed Again

Published January 28, 2016 Occasional Leave a CommentTags: Algorithms, Number Theory

Once again the record for the largest prime number has been shattered. As with all recent records, the new number is a Mersenne prime, a number of the form

*M*_{p}* = * 2^{p}* – * 1

where *p* itself is a prime. Participants in a distributed computing project called GIMPS (Great Internet Mersenne Prime Search) continue without rest to search for ever-larger primes of this form.

Most of the recent large primes have been found in the GIMPS project (for an earlier post on GIMPS, click Mersennery Quest. The project uses a search algorithm called the Lucas-Lehmer primality test, which is particularly suitable for finding Mersenne primes. The test, which was originally devised by Edouard Lucas in the nineenth century and extended by Derek Lehmer in 1930, is very efficient on binary computers.

### How many Christmas Gifts?

Published December 17, 2015 Irish Times Leave a CommentTags: Number Theory, Recreational Maths

We all know the festive carol *The Twelve Days of Christmas*. Each day, “my true love” receives an increasing number of gifts. On the first day there is one gift, a partridge in a pear tree. On the second, two turtle doves and another partridge, making three. There are six gifts on the third day, ten on the fourth, fifteen on the fifth, and so on.

Here is a Christmas puzzle: what is the total number of gifts over the twelve days? [TM083, or search for “thatsmaths” at irishtimes.com]

### The Tragic Demise of a Beautiful Mind

Published June 4, 2015 Irish Times 1 CommentTags: Algorithms, Games, Number Theory

John Nash, who was the subject of the book and film* A Beautiful Mind*, won the Abel Prize recently. But his journey home from the award ceremony in Norway ended in tragedy [see this week’s That’s Maths column (TM069): search for “thatsmaths” at irishtimes.com].

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