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Edge-graph diameter bounds for convex polytopes with few facets. (English) Zbl 1266.52017

Summary: We show that the edge graph of a 6-dimensional polytope with 12 facets has diameter at most 6, thus verifying the \(d\)-step conjecture of Klee and Walkup in the case \(d=6\). This implies that for all pairs \((d,n)\) with \(n-d\leq 6\), the diameter of the edge graph of a \(d\)-polytope with \(n\) facets is bounded by 6, which proves the Hirsch conjecture for all \(n-d\leq 6\). We prove this result by establishing this bound for a more general structure, so-called matroid polytopes, by reduction to a small number of satisfiability problems.

MSC:

52B40 Matroids in convex geometry (realizations in the context of convex polytopes, convexity in combinatorial structures, etc.)
52B05 Combinatorial properties of polytopes and polyhedra (number of faces, shortest paths, etc.)
52C40 Oriented matroids in discrete geometry

Software:

nauty

References:

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