Check if a value of type
Function:
(defun boolean-from-ullong (x) (declare (xargs :guard (and (ullongp x)))) (/= (integer-from-ullong x) 0))
Theorem:
(defthm booleanp-of-boolean-from-ullong (booleanp (boolean-from-ullong x)))
Theorem:
(defthm boolean-from-ullong-of-ullong-fix-x (equal (boolean-from-ullong (ullong-fix x)) (boolean-from-ullong x)))
Theorem:
(defthm boolean-from-ullong-ullong-equiv-congruence-on-x (implies (ullong-equiv x x-equiv) (equal (boolean-from-ullong x) (boolean-from-ullong x-equiv))) :rule-classes :congruence)