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Relations and Functions
- Importance: need basic familiarity with the terminology
- A relation on sets S and T is a set of ordered pairs (s, t), where
- s S (s
is a member of S),
- S and T need not be different,
- The set of all first elements (s) is the domain of the relation, and
- The set of all second elements is the range of the relation.
- A relation is a function iff every element of S occurs
once and only once as a first element of the relation.
- A relation is a partial function iff
every element of S occurs at most once as an element of the relation.
Copyright © 1996 by David Matuszek
Last modified Feb 2, 1996