The bunkbed conjecture is false.

Gladkov, Nikita; Pak, Igor; Zimin, Aleksandr · Proc Natl Acad Sci U S A · 2025

other · Level V

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Abstract

We give an explicit counterexample to the bunkbed conjecture introduced by Kasteleyn in 1985. The counterexample is given by a planar graph on 7,222 vertices and is built on the recent work of Hollom (2024).