mk_res_exists
res_quanLib.mk_res_exists : ((term # term # term) -> term)
Term constructor for restricted existential quantification.
mk_res_exists("var","P","t") returns "?var :: P . t".
Failure
Fails with mk_res_exists if the first term is not a variable or if P
and t are not of type ":bool".
See also
res_quanLib.dest_res_exists,
res_quanLib.is_res_exists,
res_quanLib.list_mk_res_exists