I read the proof and I'm not fully convinced, so I created a branch which includes a picture as a counterexample. Ok, I saw your counterexample picture. It is convincing me. Let's merge it to main.

welcome back to carneades.org today we're going to be continuing with our series six months of set theory and higher order logic this is logic 301 we are in month number three looking at piano ...

This repository contains a series of exercises in the Lean theorem prover that bridge mathematical logic with engineering applications. The work spans propositional logic, quantified statements, ...