RAND_CONV : (conv -> conv)
Applies a conversion to the operand of an application.
If c is a conversion that maps a term "t2" to the theorem |- t2 = t2', then the conversion RAND_CONV c maps applications of the form "t1 t2" to theorems of the form:
   |- (t1 t2) = (t1 t2')
That is, RAND_CONV c "t1 t2" applies c to the operand of the application "t1 t2".
RAND_CONV c tm fails if tm is not an application or if tm has the form "t1 t2" but the conversion c fails when applied to the term t2. The function returned by RAND_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 t to a theorem |- t = t').
- RAND_CONV numLib.num_CONV (Term `SUC 2`);
> val it = |- SUC 2 = SUC(SUC 1) : thm

HOL  Kananaskis-14