Introduction to Logic

Fitch System

The Fitch system for propositional logic is a proof system consisting of the ten rules of inference listed below. Note that nine of these are ordinary rules of inference and one (implication introduction) is a structured rule of inference.

And Introduction
And Elimination
Or Introduction
Or Elimination
Negation Introduction
Negation Elimination 		  Implication Introduction
Implication Elimination
Biconditional Introduction
Biconditional Elimination