Check if the unary minus of a value of type
Function:
(defun minus-schar-okp (x) (declare (xargs :guard (and (scharp x)))) (minus-sint-okp (sint-from-schar x)))
Theorem:
(defthm booleanp-of-minus-schar-okp (booleanp (minus-schar-okp x)))
Theorem:
(defthm minus-schar-okp-of-schar-fix-x (equal (minus-schar-okp (schar-fix x)) (minus-schar-okp x)))
Theorem:
(defthm minus-schar-okp-schar-equiv-congruence-on-x (implies (schar-equiv x x-equiv) (equal (minus-schar-okp x) (minus-schar-okp x-equiv))) :rule-classes :congruence)