Support (mathematics)

In mathematics, a support of a function f from a  set X to the  real numbers R is a subset Y of X such that f (x) is zero for all x in X and outside Y. In other words, the support Y satisfies that f {X\Y} ⊆ {0}. This concept is used very widely in mathematical analysis. In the form of functions with support that is bounded, it also plays a major part in various types of mathematical duality theories.
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