extensional equality

(Or extensionality). Functions, f and g are extensionally equal if and only if 

 f x = g x  for all x.
where "=" means both expressions fail to terminate (under some given reduction strategy) or they both terminate with the same basic value.

Two functions may be extensionally equal but not inter-convertible (neither is reducible to the other). E.g. \ x . x+x and \ x . 2*x. See also observational equivalence, referential transparency.

Nearby terms:

extensional ♦ extensional equality ♦ extensionality ♦ Extension Language Kit

Try this search on Wikipedia, Wiktionary, Google, OneLook.

Loading