(letter-charlist-p x) recognizes lists where every element satisfies letter-char-p.
(letter-charlist-p x) → std::bool
This is an ordinary std::deflist. It is
"loose" in that it does not care whether
Function:
(defun letter-charlist-p (x) (declare (xargs :guard t)) (let ((acl2::__function__ 'letter-charlist-p)) (declare (ignorable acl2::__function__)) (if (consp x) (and (letter-char-p (car x)) (letter-charlist-p (cdr x))) t)))
Theorem:
(defthm chars-in-charset-p-of-letter-chars (equal (chars-in-charset-p x (letter-chars)) (letter-charlist-p x)))