In number theory, a regular prime is a certain kind of prime number. Number theory is the branch of Pure mathematics concerned with the properties of Numbers in general and Integers in particular as well as the wider classes In Mathematics, a prime number (or a prime) is a Natural number which has exactly two distinct natural number Divisors 1 A prime number p is called regular if it does not divide the class number of the p-th cyclotomic field (that is, the algebraic number field obtained by adjoining the p-th root of unity to the rational numbers). In Mathematics, the extent to which Unique factorization fails in the ring of integers of an Algebraic number field (or more generally any Dedekind domain In Number theory, a cyclotomic field is a Number field obtained by adjoining a complex Root of unity to Q, the field of Rational numbers In Mathematics, an algebraic number field (or simply number field) F is a finite (and hence algebraic) Field extension of the In Mathematics, the n th roots of unity, or de Moivre numbers are all the Complex numbers that yield 1 when raised to a given power In Mathematics, a rational number is a number which can be expressed as a Ratio of two Integers Non-integer rational numbers (commonly called fractions Ernst Kummer showed that an equivalent criterion for regularity is that p does not divide the numerator of any of the Bernoulli numbers Bk for k = 2, 4, 6, …, p − 3. Ernst Eduard Kummer ( 29 January 1810 - 14 May 1893) was a German Mathematician. Numerator may refer to A numeral used to indicate a count particularly of the equal parts in a fraction For example in 3/4 3 is the numerator In Mathematics, the Bernoulli numbers are a Sequence of Rational numbers with deep connections to Number theory. The first few regular primes are:
It has been conjectured that there are infinitely many regular primes. In Mathematics, a conjecture is a Mathematical statement which appears resourceful but has not been formally proven to be true under the rules of Infinity (symbolically represented with ∞) comes from the Latin infinitas or "unboundedness More precisely it is conjectured (Siegel, 1964) that e−1/2, or about 61%, of all prime numbers are regular, in the asymptotic sense of natural density. The Mathematical constant e is the unique Real number such that the function e x has the same value as the slope of the tangent line In pure and Applied mathematics, particularly the Analysis of algorithms, real analysis and engineering asymptotic analysis is a method of describing In Number theory, asymptotic density or natural density is one of the possibilities to measure how large is a Subset of the set of Natural Neither conjecture has been proven as of 2008.
Historically, regular primes were first considered by Kummer, who was able to prove that Fermat's last theorem holds true for regular prime exponents (and consequently for all exponents that were multiples of regular primes). Fermat's Last Theorem is the name of the statement in Number theory that It is impossible to separate any power higher than the second into two like
An odd prime that is not regular is an irregular prime. The number of Bernoulli numbers Bk with a numerator divisible by p is called the irregularity index of p. K L Jensen has shown in 1915 that there are infinitely many irregular primes, the first few of which are: