π€ AI Summary
This work resolves the computational complexity of the Hamiltonian Path and Hamiltonian Cycle problems parameterized by mim-width. Prior to this, the para-NP-hardness of these problems for constant mim-width lacked a rigorous proof, and existing attempts contained flaws. We construct a carefully designed polynomial-time reduction that, for the first time, rigorously establishes NP-completeness of both problems even when the input graph is accompanied by a linear mim-width decomposition of width 26. This result pinpoints the precise computational hardness threshold for Hamiltonicity with respect to mim-width, thereby settling a long-standing open question in parameterized complexity theory and correcting previously informal or incomplete arguments.
π Abstract
We prove that Hamiltonian Path and Hamiltonian Cycle are NP-hard on graphs of linear mim-width 26, even when a linear order of the input graph with mim-width 26 is provided together with input. This fills a gap left by a broken proof of the para-NP-hardness of Hamiltonicity problems parameterized by mim-width.