CHOOSE_THEN : thm_tactical
A ?- s1 ========= ttac (t[x'/x] |- t[x'/x]) B ?- s2then
A ?- s1 ========== CHOOSE_THEN ttac (A' |- ?x. t) B ?- s2This is invalid unless A' is a subset of A.
LESS_ADD_1 = |- !m n. n < m ==> (?p. m = n + (p + 1))to help solve the goal
?- x < y ==> 0 < y * yby starting with the following tactic
DISCH_THEN (CHOOSE_THEN SUBST1_TAC o MATCH_MP LESS_ADD_1)which reduces the goal to
?- 0 < ((x + (p + 1)) * (x + (p + 1)))which can then be finished off quite easily, by, for example:
REWRITE_TAC[ADD_ASSOC, SYM (SPEC_ALL ADD1), MULT_CLAUSES, ADD_CLAUSES, LESS_0]