Boyer, R.S. | Moore, J.S.
We introduce the concept of the value of an expression in a binding environment which we use to standardize clauses apart and share the structure of parents in representing the resolvent. Lists provide the most obvious and natural representation of literals because lists perfectly reflect function nesting structure. Therefore, we introduce the concepts of an expression, a binding environment, and the value of an expression in a binding environment. If VALI and VA L2 have no common instance, then the call will return false.