Get the witness field from a type-subset.
(type-subset->witness x) → witness
This is an ordinary field accessor created by fty::defprod.
Function:
(defun type-subset->witness$inline (x) (declare (xargs :guard (type-subsetp x))) (declare (xargs :guard t)) (let ((__function__ 'type-subset->witness)) (declare (ignorable __function__)) (mbe :logic (b* ((x (and t x))) (maybe-expression-fix (cdr (std::da-nth 3 x)))) :exec (cdr (std::da-nth 3 x)))))
Theorem:
(defthm maybe-expressionp-of-type-subset->witness (b* ((witness (type-subset->witness$inline x))) (maybe-expressionp witness)) :rule-classes :rewrite)
Theorem:
(defthm type-subset->witness$inline-of-type-subset-fix-x (equal (type-subset->witness$inline (type-subset-fix x)) (type-subset->witness$inline x)))
Theorem:
(defthm type-subset->witness$inline-type-subset-equiv-congruence-on-x (implies (type-subset-equiv x x-equiv) (equal (type-subset->witness$inline x) (type-subset->witness$inline x-equiv))) :rule-classes :congruence)