ABS_CONV : conv -> conv
Applies a conversion to the body of an abstraction.
If c is a conversion that maps a term tm to the theorem |- tm = tm', then the conversion ABS_CONV c maps abstractions of the form \x.tm to theorems of the form:
   |- (\x.tm) = (\x.tm')
That is, ABS_CONV c (\x.t) applies c to the body of the abstraction \x.t.
ABS_CONV c tm fails if tm is not an abstraction or if tm has the form \x.t but the conversion c fails when applied to the term t. The function returned by ABS_CONV c may also fail if the ML function c:term->thm is not, in fact, a conversion (i.e. a function that maps a term M to a theorem |- M = N).
- ABS_CONV SYM_CONV (Term `\x. 1 = x`)
> val it = |- (\x. 1 = x) = (\x. x = 1) : thm

HOL  Kananaskis-14