Neuen-Grohe Problem: Isomorphism of Tournaments with Bounded VC Dimension
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Statement
Among classes of tournaments for which neither hardness nor polynomial-time solvability of isomorphism was known, bounded VC dimension stood out as an open problem of Neuen and Grohe. Resolved: isomorphism of tournaments of VC dimension is decidable in time , so automorphism groups of bounded-VC tournaments are computable in polynomial time; isomorphism of tournaments of bounded chromatic number is also polynomial-time decidable.
Context
A posed open problem in the graph-isomorphism literature after Babai's quasipolynomial breakthrough, from named experts, with a clean parameterized resolution. Specialist - just above the numbered-problem band.
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The statement of AI use names two specific steps: the proof of one preliminary lemma (the tournament VC-dimension lemma) was provided by Claude Sonnet 5, and the proof of a second bound was simplified by it. Named model-contributed lemmas inside a human-led argument.
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