Recognizer for bin-digit.
(bin-digitp x) → yes/no
Function:
(defun bin-digitp (x) (declare (xargs :guard t)) (let ((__function__ 'bin-digitp)) (declare (ignorable __function__)) (or (eql x (char-code #\0)) (eql x (char-code #\1)))))
Theorem:
(defthm booleanp-of-bin-digitp (b* ((yes/no (bin-digitp x))) (booleanp yes/no)) :rule-classes :rewrite)