FUN_EQ_CONV
Conv.FUN_EQ_CONV : conv
Equates normal and extensional equality for two functions.
The conversion FUN_EQ_CONV embodies the fact that two functions are
equal precisely when they give the same results for all values to which
they can be applied. When supplied with a term argument of the form
f = g, where f and g are functions of type ty1->ty2,
FUN_EQ_CONV returns the theorem:
|- (f = g) = (!x. f x = g x)
where x is a variable of type ty1 chosen by the conversion.
Failure
FUN_EQ_CONV tm fails if tm is not an equation f = g, where f and
g are functions.
Used for proving equality of functions.