CS245 Study Guide - Proof Calculus, Soundness, Natural Deduction
Document Summary
Mat 3361, introduction to mathematical logic, fall 2004. These notes are based on raymond m. smullyan, first-order logic . A signed formula is an expression t x or f x, where x is an (un- signed) formula. Under a given valuation, a signed formula t x is called true if. X is true, and false if x is false. Also, a signed formula f x is called true if x is false, and false if x is true. We begin with the following observations about signed formulas: T (x y ) t x and t y . F (x y ) f x or f y . T (x y ) t x or t y . F (x y ) f x and f y . T (x y ) f x or t y . F (x y ) t x and f y .
