GEN_IMP : term -> thm -> thm
          A |- (t1 ==> t2)
   ----------------------------     GEN_IMP x       [where x is not free in A]
    A |- (!x. t1) ==> (!x. t2)
- val thm0 = mk_thm ([], Term `P (x:'a) ==> Q x`); > val thm0 = |- P (x :'a) ==> Q x : thm - val thm1 = GEN_IMP (Term `x:'a`) thm0; > val thm1 = |- (!x. P x) ==> (!x. Q x)