CIS 1166 Lecture : Models(1).pdf
Document Summary
This short note is about the predicate calculus with equality. I assume that it always make sense to ask of two things whether or not they are equal. For any other predicate p, we have to specify the domains of the various inputs to the predicate. If we have a proposition in the predicate calculus, we might want to know whether our proposition is true or not. Instead of writing x+y = z or x+y < z, we write l(x, y, z) to mean x+y = z and w(l(x, y, w) w < z) to mean x + y < z. To say i know about all about all predicates is to say that i know which legal combinations of inputs to a predicate result in output true and which result in output false. What i know when i know all about all the predicates, i call a model.