Keyword:Four-Color Theorem

Publications
Hilbert Mathematics Versus Gödel Mathematics. IV. the New Approach of Hilbert Mathematics Easily Resolving the Most Difficult Problems of Gödel Mathematics Vasil Penchev EasyChair Preprint 10610
From the Four-Colors Theorem to a Generalizing “Four-Letters Theorem”: a Sketch for “Human Proof” and the Philosophical Interpretation Vasil Penchev EasyChair Preprint 3194