a partial function from a set to a set is an assignment to each element in a subset of , called the domain of definition of , of a unique element in . the sets and are called the domain and codomain of , respectively. we say that is undefined for elements in that are not in the domain of definition of . when the domain of definition of equals . we say that is a total function.
some stuff from college
let be non-empty sets and let be a relation from to
we say is a partial function from to if is single-valued meaning that for every there exists at most a single such that
equality of partial functions
the functions are equal if:
of the following functions only 2 are equal