FILTER_STRIP_THEN : (thm_tactic -> term -> tactic)
FILTER_STRIP_THEN behaves like STRIP_GOAL_THEN, if the term being stripped does not contain a free instance of u. In particular, FILTER_STRIP_THEN STRIP_ASSUME_TAC behaves like FILTER_STRIP_TAC.
?- (n = 1) ==> (n * n = n)the application of FILTER_STRIP_THEN SUBST1_TAC "m:num" results in the goal
?- 1 * 1 = 1