## Quick Reference

*S*, with respect to some universal set *U*. The set consisting of elements that are in *U* but not in *S*; it is usually denoted by *S*′, ~*S*, or *S¯*. Formally, *S*′ = {*x* | (*x* ∈ *U*) and (*x* ∉ *S*)} The process of taking complements is one of the basic operations that can be performed on sets.

*S*′ = {*x* | (*x* ∈ *U*) and (*x* ∉ *S*)}

The set difference (or relative complement) of two sets *S* and *T* is the set of elements that are in *S* but not in *T*; it is usually written as *S* – *T*. Thus *S*′ = *U* – *S* See also operations on sets.

*S*′ = *U* – *S*

*G*′, with vertices *V*′ and edges *E*′, of a graph *G*, with vertices *V* and edges *E*. The subgraph consisting of the vertices *V* and the edges in *E* but not in *E*′.

**From:**
complement
in
A Dictionary of Computing »

*Subjects:*
Computing.