1,733 articles
73 (number)
73, or seventy-three, is the 21st prime number that Sheldon Cooper called the best number on The Big Bang Theory; it is also the atomic number of tantalum.
777 (number)
777 is the natural number following 776, best known as the triple-seven jackpot symbol on slot machines and a sphenic, palindromic, Harshad number in number theory.
786 (number)
786 is an even composite number whose prime factorization is 2 × 3 × 131, known culturally as the Abjad value of the Bismillah in South Asia.
8 (number)
8 (eight), the natural number following 7 and preceding 9, is the cube of 2, the sixth Fibonacci number, and the number of bits in a byte.
80 (number)
80 is the natural number following 79, a composite abundant number with ten divisors, the atomic number of mercury, and the number French names quatre-vingts, four twenties.
88 (number)
88 (eighty-eight) is the natural number after 87, best known as the number of keys on a piano, the constellations recognized by the IAU, and radium's atomic number.
89 (number)
89, or eighty-nine, is the natural number after 88 and before 90. It is the 24th prime, the 11th Fibonacci number, and actinium's atomic number.
9 (number)
9 (nine) is the natural number following 8 and preceding 10: the largest single digit, the square of 3, and the smallest odd composite number, basis of casting out nines.
90 (number)
90 (ninety), the natural number following 89 and preceding 91, is an abundant pronic number with twelve divisors, best known as the degree measure of a right angle.
A History of Vector Analysis
A History of Vector Analysis is the history of how modern vector analysis, built from Hamilton's quaternions and Grassmann's extension theory, became the standard language of physics.
A¹ homotopy theory
A¹ homotopy theory, also called motivic homotopy theory, is a homotopy theory for algebraic geometry developed by Fabien Morel and Vladimir Voevodsky in the 1990s.
Abc conjecture
The abc conjecture, also known as the Oesterlé–Masser conjecture, is a 1985 conjecture in number theory about coprime integers satisfying a + b = c.
Abel–Jacobi map
The Abel–Jacobi map is the canonical homomorphism sending the degree-zero divisor classes of an algebraic curve to its Jacobian variety, defined by integrating holomorphic differentials along paths.
Abel–Ruffini theorem
The Abel–Ruffini theorem, also known as Abel's impossibility theorem, states that no formula in radicals can solve general polynomial equations of degree five or higher.
Abelian category
An abelian category is a mathematical category, axiomatized by Alexander Grothendieck in 1957, in which kernels, images, and exact sequences behave as they do for modules over a ring.
Abelian extension
An abelian extension is a Galois field extension whose Galois group is abelian; class field theory classifies such extensions of number fields by ray class groups.
Abelian group
An abelian group, or commutative group, is a group in which the group operation is commutative: xy = yx for all elements, named for Niels Henrik Abel.
Abelian variety
An abelian variety is a complete algebraic variety equipped with a commutative group structure, a higher-dimensional generalization of elliptic curves central to algebraic geometry and cryptography.
Abelianization
Abelianization is a construction in group theory that turns a group into its maximal abelian quotient by dividing out the subgroup generated by all commutators.
Absolute Galois group
The absolute Galois group of a field K is the Galois group of its separable closure, a profinite topological group that packages the Galois theory of all algebraic extensions.
Absolute value
Absolute value, also called modulus, is the magnitude of a real or complex number without regard to its sign, written |x|, the distance from zero on the number line.
Abstract algebra
Abstract algebra, also called modern algebra, is the branch of mathematics that studies algebraic structures like groups, rings, and fields, rather than computing with particular number systems.
Abundant number
An abundant number, or excessive number, is a positive integer whose proper divisors add up to more than the number itself, the smallest being 12.
Adder (electronics)
An adder, also known as a binary adder, is a digital logic circuit that adds numbers, typically in binary, serving as a building block of processors and ALUs.
Addition
Addition is the basic arithmetic operation combining two summands into a sum, written a + b; it is commutative and associative, with subtraction as its inverse.
Addition-chain exponentiation
Addition-chain exponentiation is a method for computing a power of a group element using an addition chain for the exponent, with one multiplication per step, minimizing multiplications in cryptography.
Additive basis
An additive basis is a set of integers from which every integer can be written as a sum of a bounded number of elements, studied in additive number theory.
Additive category
An additive category is a category in which morphisms between any two objects form abelian groups and finite direct sums exist, the setting for algebraic K-theory and abelian categories.
Additive combinatorics
Additive combinatorics, also called arithmetic combinatorics, is a branch of mathematics studying combinatorial properties of algebraic objects such as Abelian groups, rings, and fields, centered on sumsets and small doubling.
Additive function
An additive function, or additive arithmetic function, is an arithmetic function satisfying f(mn) = f(m) + f(n) for relatively prime integers m and n; log n is completely additive.