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Sexpr-equivs

4v-cdr-equiv

Weaker version of element equivalence for four-valued alists.

This is a universal equivalence, introduced using def-universal-equiv.

Function: 4v-cdr-equiv

(defun 4v-cdr-equiv (x y)
  (and (4v-equiv (cdr x) (cdr y))))

Definitions and Theorems

Function: 4v-cdr-equiv

(defun 4v-cdr-equiv (x y)
  (and (4v-equiv (cdr x) (cdr y))))

Theorem: 4v-cdr-equiv-is-an-equivalence

(defthm 4v-cdr-equiv-is-an-equivalence
  (and (booleanp (4v-cdr-equiv x y))
       (4v-cdr-equiv x x)
       (implies (4v-cdr-equiv x y)
                (4v-cdr-equiv y x))
       (implies (and (4v-cdr-equiv x y)
                     (4v-cdr-equiv y z))
                (4v-cdr-equiv x z)))
  :rule-classes (:equivalence))

Theorem: 4v-cdr-equiv-implies-4v-equiv-cdr-1

(defthm 4v-cdr-equiv-implies-4v-equiv-cdr-1
  (implies (4v-cdr-equiv x x-equiv)
           (4v-equiv (cdr x) (cdr x-equiv)))
  :rule-classes (:congruence))