Carl Theodore Heisel (1852–1937) was a mathematical crank who wrote several books in the 1930s challenging accepted mathematical truths. Among his claims is that he found a way to square the circle. He is credited with 24 works in 62 publications. Heisel did not charge money for his books; he gave thousands of them away for free. Because of this, they are available at many libraries and universities. Heisel's books have historic and monetary value. Paul Halmos referred to one of Heisel's works as a "classic crank book."
Selected works
- Heisel, Carl Theodore (1934). Mathematical and geometrical demonstrations, disproving numerous theorems, problems, postulates, corolleries, axioms naturally growing out of the extraordinary discoveries of a lacking link (2d. ed.). Cleveland.
References
- "Carl Theodore Heisel (1852–1937)". Find a Grave. Retrieved 31 May 2019.
- "WorldCat Listing". Retrieved 16 May 2019.
- Simanek, Donald E. "Carl Theodore Heisel Squares the Circle". lockhaven.edu. Archived from the original on 26 February 2021. Retrieved 23 May 2019.
- Paul R. Halmos (1970). "How to Write Mathematics". L'Enseignement mathématique. 16 (2): 123–152. – How to Write Mathematics