Logic & Foundations with Haskell: Logic 8 :: Soundness of Natural Deduction for Propositional Logic
Channel: Marius Furter
Date: 2023-04-18

We show that the natural deduction proof calculus is sound for propositional logic, meaning that it only proves true formulas given true assumptions.

00:00 Introduction
00:33 Definition: Model for a set of formulas, semantic sequents
03:45 Thm: Soundness of natural deduction
05:30 Proof of soundness theorem

The playlist for the course can be found here: https://www.youtube.com/watch?v=0HImO-me_sg&list=PLd8NbPjkXPliojM8YMN3z3o9--zXwti8Z