In May 2016 he, along with Oliver Kullmann and Victor W. Marek, used SAT solving to solve the Boolean Pythagorean triples problem.[3][4] The statement of the theorem they proved is
Theorem — The set {1, . . . , 7824} can be partitioned into two parts, such that no part contains a Pythagorean triple, while this is impossible for {1, . . . , 7825}.[5]
To prove this theorem, the possible colorings of {1, ..., 7825} were divided into a trillion subcases using a heuristic. Each subclass was then solved a Boolean satisfiability solver. Creating the proof took about 4 CPU-years of computation over a period of two days on the Stampede supercomputer at the Texas Advanced Computing Center and generated a 200 terabyte propositional proof (which was compressed to 68 gigabytes in the form of the list of subcases used).[5] The paper describing the proof was published in the SAT 2016 conference,[5] where it won the best paper award.[5] A $100 award that Ronald Graham originally offered for solving this problem in the 1980s was awarded to Heule.[3]
^ abcdHeule, Marijn J. H.; Kullmann, Oliver; Marek, Victor W. (2016). "Solving and Verifying the Boolean Pythagorean Triples problem via Cube-and-Conquer". In Creignou, Nadia; Le Berre, Daniel (eds.). Theory and Applications of Satisfiability Testing – SAT 2016: 19th International Conference, Bordeaux, France, July 5-8, 2016, Proceedings. Lecture Notes in Computer Science. Vol. 9710. pp. 228–245. arXiv:1605.00723. doi:10.1007/978-3-319-40970-2_15. ISBN978-3-319-40969-6.
^Subercaseaux, Bernardo; Heule, Marijn J. H. (January 23, 2023). "The Packing Chromatic Number of the Infinite Square Grid is 15". arXiv:2301.09757 [cs.DM].