Replace each if with if* in a term.
(fty-if-to-if* term) → term1
Theorem:
(defthm return-type-of-fty-if-to-if*.term1 (b* ((?term1 (fty-if-to-if* term))) (pseudo-termp term1)) :rule-classes :rewrite)
Theorem:
(defthm return-type-of-fty-if-to-if*-lst.terms1 (b* ((?terms1 (fty-if-to-if*-lst terms))) (pseudo-term-listp terms1)) :rule-classes :rewrite)
Theorem:
(defthm len-of-fty-if-to-if*-lst (b* ((?terms1 (fty-if-to-if*-lst terms))) (equal (len terms1) (len terms))))