PFORALL_EQ : (term -> thm -> thm)
A |- t1 = t2
whose conclusion is an equation between boolean terms:
PFORALL_EQ
returns the theorem:
A |- (!p. t1) = (!p. t2)
unless any of the variables in p is free in any of the assumptions.
A |- t1 = t2
-------------------------- PFORALL_EQ "p" [where p is not free in A]
A |- (!p. t1) = (!p. t2)