A Proof of the Four-Color Problem based on a New Law of Logic the Law of the Middle Term

Abstract

The Four-Color Conjecture, also known as the Four-Color Problem, was first proposed by Francis Guthrie, an Englishman, in 1852. The most famous previous proof of this problem was made by Kenneth Appel and Wolfgang Haken in the United States in 1976 using computers. Afterwards, there are still a considerable number of people hoping to find an artificial proof of this problem. My paper titled "A Logical Proof of the Four-Color Problem" was published in the Journal of Applied Mathematics and Physics in May 2020. Later, it was found that the key logical proof part can form a new logical law — the law of the middle term. This paper aims to give a proof of the Four-Color Problem based on the law of the middle term in logic proposed in this paper, so that the proof idea is clearer, the proof process is more rigorous, and more concise. While solving the problem of graph theory, also made a little contribution to the development of logic.