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The definition

Letas well as the definitionfbe a binary relation.fis apartial functionif every element of its domain is in relation to at most one element of its range.

Aare to be read as the definition of a unary predicatepartial functionis a binary relation where every element of the domain is in relation to at most one element of the range.

fis a partial function : <=>

fis a binary relation /\

forallx,y_0,y_1: (<x,y_0> inf/\ <x,y_1> inf) =>y_0 =y_1.

Author: Wolfgang Schreiner

Last Modification: October 14, 1999