Complement may refer to:

The arts

* Complement (music), an interval that, when added to another, spans an octave ** Aggregate complementation, the separation of pitch-class collections into complementary sets * Complementary color, in the visual arts

Biology and medicine

Complement system The complement system, also known as complement cascade, is a part of the humoral, innate immune system and enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inf ...

(immunology), a cascade of proteins in the blood that form part of innate immunity * Complementary DNA, DNA reverse transcribed from a mature mRNA template *

Complementarity (molecular biology) In molecular biology, complementarity describes a relationship between two structures each following the lock-and-key principle. In nature complementarity is the base principle of DNA replication and transcription as it is a property shared b ...

, a property whereby double stranded nucleic acids pair with each other * Complementation (genetics), a test to determine if independent recessive mutant phenotypes are caused by mutations in the same gene or in different genes

Grammar and linguistics

Complement (linguistics) In grammar, a complement is a word, phrase, or clause that is necessary to complete the meaning of a given expression. Complements are often also arguments (expressions that help complete the meaning of a predicate). Predicative, subject and ob ...

, a word or phrase having a particular syntactic role **

Subject complement In traditional grammar, a subject complement is a predicative expression that follows a copula (commonly known as a linking verb), which complements the subject of a clause by means of characterization that completes the meaning of the subject. ...

, a word or phrase adding to a clause's subject after a linking verb **

Object complement In grammar, an object complement is a predicative expression that follows a direct object of an attributive ditransitive or resultative verb and that complements the direct object of the sentence by describing it. Object complements are constit ...

, a word or phrase adding to the direct object of a verb phrase. *

Phonetic complement A phonetic complement is a phonetic symbol used to disambiguate word characters (logograms) that have multiple readings, in mixed logographic-phonetic scripts such as Egyptian hieroglyphs, Akkadian cuneiform, Linear B, Japanese, and Mayan. O ...

* Complementary, a type of opposite in lexical semantics (sometimes called an antonym)

Mathematics

Algebra

* Complement (group theory) * Complementary subspaces *

Orthogonal complement In the mathematical fields of linear algebra and functional analysis, the orthogonal complement of a subspace W of a vector space V equipped with a bilinear form B is the set W^\perp of all vectors in V that are orthogonal to every vector in W. I ...

* Schur complement

Algorithms

* Complement (complexity), relating to decision problems and complexity classes *

Complement operator (regular expressions) A regular expression (shortened as regex or regexp), sometimes referred to as rational expression, is a sequence of characters that specifies a match pattern in text. Usually such patterns are used by string-searching algorithms for "find" ...

* Method of complements, in computer science ** Radix complement ** Diminished radix complement **

Ones' complement The ones' complement of a binary number is the value obtained by inverting (flipping) all the bits in the Binary number, binary representation of the number. The name "ones' complement" refers to the fact that such an inverted value, if added t ...

Two's complement Two's complement is the most common method of representing signed (positive, negative, and zero) integers on computers, and more generally, fixed point binary values. Two's complement uses the binary digit with the ''greatest'' value as the ''s ...

Discrete mathematics

Complement graph In the mathematical field of graph theory, the complement or inverse of a graph is a graph on the same vertices such that two distinct vertices of are adjacent if and only if they are not adjacent in . That is, to generate the complement of ...

Self-complementary graph In the mathematical field of graph theory, a self-complementary graph is a graph which is isomorphic to its complement. The simplest non-trivial self-complementary graphs are the path graph and the cycle graph. There is no known characteri ...

, a graph which is isomorphic to its complement *

Complemented lattice In the mathematics, mathematical discipline of order theory, a complemented lattice is a bounded lattice (order), lattice (with least element 0 and greatest element 1), in which every element ''a'' has a complement, i.e. an element ''b'' satisfyin ...

Geometry

* Complement of an angle, the difference between a right angle (90 degrees) and a given angle *

Knot complement In mathematics, the knot complement of a tame knot ''K'' is the space where the knot is not. If a knot is embedded in the 3-sphere, then the complement is the 3-sphere minus the space near the knot. To make this precise, suppose that ''K'' is a ...

* Complement of a point, the dilation of a point in the

centroid In mathematics and physics, the centroid, also known as geometric center or center of figure, of a plane figure or solid figure is the arithmetic mean position of all the points in the figure. The same definition extends to any object in n-d ...

of a given triangle, with ratio −1/2

Logic

Complement (set theory) In set theory, the complement of a Set (mathematics), set , often denoted by A^c (or ), is the set of Element (mathematics), elements not in . When all elements in the Universe (set theory), universe, i.e. all elements under consideration, are c ...

Complementary event In probability theory, the complement of any event ''A'' is the event ot ''A'' i.e. the event that ''A'' does not occur.Robert R. Johnson, Patricia J. Kuby: ''Elementary Statistics''. Cengage Learning 2007, , p. 229 () The event ''A'' and ...

in probability *

Logical complement In logic, negation, also called the logical not or logical complement, is an operation that takes a proposition P to another proposition "not P", written \neg P, \mathord P, P^\prime or \overline. It is interpreted intuitively as being true ...

Bitwise complement In computer programming, a bitwise operation operates on a bit string, a bit array or a binary numeral (considered as a bit string) at the level of its individual bits. It is a fast and simple action, basic to the higher-level arithmetic operatio ...

* Complements in

boolean algebra In mathematics and mathematical logic, Boolean algebra is a branch of algebra. It differs from elementary algebra in two ways. First, the values of the variable (mathematics), variables are the truth values ''true'' and ''false'', usually denot ...

Other uses

* Complementary experiments, in physics *

Complement good In economics, a complementary good is a good whose appeal increases with the popularity of its complement. Technically, it displays a negative cross elasticity of demand and that demand for it increases when the price of another good decreases ...

(economics), a good often consumed together with another good * Ship's complement, the number of persons in a ship's company