Specializes the conclusion of a theorem with its own quantified variables.
When applied to a theorem A |- !x1...xn. t, the inference rule SPEC_ALL
returns the theorem A |- t[x1'/x1]...[xn'/xn] where the xi' are distinct
variants of the corresponding xi, chosen to avoid clashes with any variables
free in the assumption list. Normally xi' is just xi, in which case
SPEC_ALL simply removes all universal quantifiers.
A |- !x1...xn. t
A |- t[x1'/x1]...[xn'/xn]
The following example shows how variables are also renamed to avoid clashing
with those in assumptions.
# let th = ADD_ASSUM `m = 1` ADD_SYM;;
val th : thm = m = 1 |- !m n. m + n = n + m
# SPEC_ALL th;;
val it : thm = m = 1 |- m' + n = n + m'