In the case of propositional logic, deduction comes down to applications of the transitive law for conditional implications. Employing a few "terms of art" from classical logic that are still useful in treating these kinds of problems, deduction takes a Case, the minor premiss <math>X \Rightarrow Y,</math> and combines it with a Rule, the major premiss <math>Y \Rightarrow Z,</math> to arrive at a Fact, the demonstrative conclusion <math>X \Rightarrow Z.</math>