Proves equivalence of two disjunctions containing same set of disjuncts.
DESCRIPTION
The call DISJ_ACI_RULE `t1 \/ ... \/ tn <=> u1 \/ ... \/ um`, where both
sides of the equation are disjunctions of exactly the same set of disjuncts,
(with arbitrary ordering, association, and repetitions), will return the
corresponding theorem |- t1 \/ ... \/ tn <=> u1 \/ ... \/ um.
FAILURE CONDITIONS
Fails if applied to a term that is not a Boolean equation or the two sets of
disjuncts are different.
EXAMPLE
# DISJ_ACI_RULE `(p \/ q) \/ (q \/ r) <=> r \/ q \/ p`;;
val it : thm = |- (p \/ q) \/ q \/ r <=> r \/ q \/ p
COMMENTS
The same effect can be had with the more general AC construct. However, for
the special case of disjunction, DISJ_ACI_RULE is substantially more
efficient when there are many disjuncts involved.