dest_pairpairSyntax.dest_pair : term -> term * term
Breaks apart a pair into two separate terms.
dest_pair is a term destructor for pairs: if
M is a term of the form (t1,t2), then
dest_pair M returns (t1,t2).
Fails if M is not a pair.
pairSyntax.mk_pair, pairSyntax.is_pair, pairSyntax.strip_pair