These files accompany the paper arXiv:2602.05095.
The formal proofs provided in this work were developed and verified using Lean 4.26.0. Compatibility with earlier or later versions is not guaranteed due to the evolving nature of the Lean 4 compiler and its core libraries.
After we posted the first version on arXiv, we learned from K. Soundararajan that the result in this paper was previously obtained by Mirsky in 1947.
dead-ends.tex: natural language description of the problemtask.md: description of the task to be completed (deferring todead-ends.tex).environment: specifies the Lean version
Deadends/problem.lean: translation of the problem statement into formal language (Lean), including the answer itself (computed by AxiomProver)Deadends/solution.lean: solution in formal language (Lean)
This repository uses the MIT License. See LICENSE for details.