PCHOOSE_THEN : thm_tactical
STRUCTURE
LIBRARY
pair
SYNOPSIS
Applies a tactic generated from the body of paired existentially quantified theorem.
DESCRIPTION
When applied to a theorem-tactic ttac, a paired existentially quantified theorem:
    A' |- ?p. t

and a goal, CHOOSE_THEN applies the tactic ttac (t[p'/p] |- t[p'/p]) to the goal, where p' is a variant of the pair p chosen to have no components free in the assumption list of the goal. Thus if:

    A ?- s1
   =========  ttac (t[q'/q] |- t[q'/q])
    B ?- s2
then
    A ?- s1
   ==========  CHOOSE_THEN ttac (A' |- ?q. t)
    B ?- s2
This is invalid unless A' is a subset of A.
FAILURE
Fails unless the given theorem is a paired existential quantification, or if the resulting tactic fails when applied to the goal.
SEEALSO
HOL  Kananaskis-10