Moves a universal quantification inwards through a disjunction.
DESCRIBE
When applied to a term of the form !x. P \/ Q, where x is not free in both
P and Q, FORALL_OR_CONV returns a theorem of one of three forms,
depending on occurrences of the variable x in P and Q. If x is free
in P but not in Q, then the theorem:
|- (!x. P \/ Q) = (!x.P) \/ Q
is returned. If x is free in Q but not in P, then the
result is:
|- (!x. P \/ Q) = P \/ (!x.Q)
And if x is free in neither P nor Q, then the result is:
|- (!x. P \/ Q) = (!x.P) \/ (!x.Q)
FAILURE
FORALL_OR_CONV fails if it is applied to a term not of the form
!x. P \/ Q, or if it is applied to a term !x. P \/ Q in which the
variable x is free in both P and Q.