closure

…is said to be a closed wff of LPC. If a wff of LPC is considered as a proposition form, instances of it are obtained by replacing all free variables in it by predicates or by names of individuals, as appropriate. A bound variable, on the other hand, indicates not…

…a closed wff (called a closure of α) that will express a determinate proposition when a meaning is assigned to the predicate variables. The above rules can be used to list exhaustively the nonequivalent closures of α and the implication relations between them. The simplest example is ϕxy, which for…