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