# Sum

Sum most commonly means the total of two or more numbers added together; see addition.
Sum can also refer to:

## Mathematics

* Sum (category theory), the generic concept of summation in mathematics
* Sum, the result of summation, the addition of a sequence of numbers
* 3SUM, a term from computational complexity theory
* Band sum, a way of connecting mathematical knots
* Connected sum, a way of gluing manifolds
* Digit sum, in number theory
* Direct sum, a combination of algebraic objects
** Direct sum of groups
** Direct sum of modules
** Direct sum of permutations
** Direct sum of topological groups
* Einstein summation, a way of contracting tensor indices
* Empty sum, a sum with no terms
* Indefinite sum, the inverse of a finite difference
* Kronecker sum, an operation considered a kind of addition for matrices
* Matrix addition, in linear algebra
* Minkowski addition, a sum of two subsets of a vector space
* Power sum symmetric polynomial, in commutative algebra
* Prefix sum, in computing
* Pushout (category theory) (also called an amalgamated sum or a cocartesian square, fibered coproduct, or fibered sum), the colimit of a diagram consisting of two morphisms f : Z → X and g : Z → Y with a common domainor pushout, leading to a fibered sum in category theory
* QCD sum rules, in quantum field theory
* Riemann sum, in calculus
* Rule of sum, in combinatorics
* Subset sum problem, in cryptography
* Sum rule in differentiation, in calculus
* Sum rule in integration, in calculus
* Sum rule in quantum mechanics
* Wedge sum, a one-point union of topological spaces
* Whitney sum, of fiber bundles
* Zero-sum problem in combinatorics

## Computing and technology

* Sum (Unix), a program for generating checksums
* StartUp-Manager, a program to configure GRUB, GRUB2, Usplash and Splashy
* Sum type, a computer science term

## Art and entertainment

* Sum, the first beat (pronounced like "some") in any rhythmic cycle of Hindustani classical music
* "Sum", a song by Pink Floyd from The Endless River
* Sum: Forty Tales from the Afterlives, a 2009 collection of short stories by David Eagleman
* Sum 41, a Canadian punk band
* SUM, the computer in Goat Song (novelette) story by Poul Anderson in Magazine of Fantasy and Science Fiction, (1972).

## Organizations

* Senter for utvikling og miljø (Centre for Development and the Environment), a research institute which is part of the University of Oslo
* Soccer United Marketing, the for-profit marketing arm of Major League Soccer
* Society for the Establishment of Useful Manufactures, a now-defunct private state-sponsored corporation founded in 1791 to promote industrial development along the Passaic River in New Jersey in the United States
* The State University of Management, a Russian university
* Save Uganda Movement, a Ugandan militant opposition group
* Ukrainian Youth Association (Спілка української молоді, Spilka Ukraïns'koï Molodi), a youth organization in Ukraine and countries with a Ukrainian diaspora

## Places

* Sum (administrative division), an administrative division in Mongolia, China, and some areas of Russia
** Sum (Mongolia), an administrative division of Mongolia
* SUM, the IATA airport code for the Sumter Airport in Sumter County, South Carolina, U.S.

## Other uses

* Sum, an old name for the Finns in East Slavic languages, derived from the word Suomi, "Finland"
* Soum (currency) (also spelled "sum"), a unit of currency used in some Turkic-speaking countries of Central Asia
* SUM (interbank network), an interbank network in 42 U.S. states
* SUM, the ISO 639-3 code for the Sumo language
* Cen (surname) 岑, a Chinese surname sometimes romanized as Sum
* Shěn (surname) 沈, a Chinese surname sometimes romanized as Sum
* Cogito, ergo sum, Latin for: "I think, therefore I am"
* Sum certain, a legal term