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Subset
From Mathematics Is A Science
Revision as of 05:26, 21 February 2011 by imported>WikiSysop
A set $A$ is a subset of set $X$ if every element of $A$ is also an element of $X$.
For every subset $A$, such function is defined as inclusion.
Given a function $f:X \rightarrow Y$, for every subset $A$ such function as restriction is defined.