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.

## Posts Tagged 'Primes'

### A Geometric Sieve for the Prime Numbers

Published April 27, 2017 Occasional ClosedTags: Number Theory, Primes

### Fermat’s Christmas Theorem

Published December 25, 2014 Occasional ClosedTags: Arithmetic, Number Theory, Pi, Primes, Spherical Trigonometry

Albert Girard (1595-1632) was a French-born mathematician who studied at the University of Leiden. He was the first to use the abbreviations ‘sin’, ‘cos’ and ‘tan’ for the trigonometric functions.

### Waring’s Problem & Lagrange’s Four-Square Theorem

Published October 23, 2014 Occasional ClosedTags: Gauss, Number Theory, Primes, Ramanujan

**Introduction**

We are all familiar with the problem of splitting numbers into products of primes. This process is called *factorisation*. The problem of expressing numbers as *sums* of smaller numbers has also been studied in great depth. We call such a decomposition a partition. The Indian mathematician Ramanujan proved numerous ingenious and beautiful results in partition theory.

More generally, **additive number theory** is concerned with the properties and behaviour of integers under addition. In particular, it considers the expression of numbers as sums of components of a particular form, such as powers. Waring’s Problem comes under this heading.

Continue reading ‘Waring’s Problem & Lagrange’s Four-Square Theorem’

### The Prime Number Theorem

Published February 27, 2014 Occasional ClosedTags: Analysis, Arithmetic, Gauss, Number Theory, Primes

*God may not play dice with the Universe, but something strange is going on with the prime numbers* [Paul Erdös, paraphrasing Albert Einstein]

The prime numbers are the atoms of the natural number system. We recall that a prime number is a natural number greater than one that cannot be broken into smaller factors. Every natural number greater than one can be expressed in a unique way as a product of primes. Continue reading ‘The Prime Number Theorem’

This week, *That’s Maths* in the *Irish Times* ( TM022 ) reports on two exciting recent breakthroughs in prime number theory.

The mathematics we study at school gives the impression that all the big questions have been answered: most of what we learn has been known for centuries, and new developments are nowhere in evidence. In fact, research in maths has never been more intensive and advances are made on a regular basis.

### A Mersennery Quest

Published November 1, 2012 Irish Times ClosedTags: History, Number Theory, Primes

**The theme of That’s Maths (TM008) this week is prime numbers. Almost all the largest primes found in recent years are of a particular form **

*M*(

*n*)

*=*2

^{n}

*−*1

**. They are called Mersenne primes. The**Continue reading ‘A Mersennery Quest’

*Great Internet Mersenne Prime Search*(GIMPS) is aimed at finding ever more prime numbers of this form.