extensional equality
extensional equality
f x = g x for all x.
where "=" means both expressions fail to terminate (under somegiven reduction strategy) or they both terminate with thesame basic value.
Two functions may be extensionally equal but notinter-convertible (neither is reducible to the other). E.g.\\ x . x+x and \\ x . 2*x. See also observational equivalence, referential transparency.