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The maximum number of faces of the Minkowski sum of three convex polytopes

2012/11/26 by Karavelas, Menelaos I., Konaxis, Christos, Tzanaki, Eleni
#52B05 #52B11 #52C45 #68U05 #Combinatorics (math.CO) #Computational Geometry (cs.CG) #F.2.2 #FOS: Computer and information sciences #FOS: Mathematics

paper · doi:10.48550/arxiv.1211.6089

Abstract

We derive tight expressions for the maximum number of k-faces, 0≤ k≤ d-1, of the Minkowski sum, P1+P2+P3, of three d-dimensional convex polytopes P1, P2 and P3, as a function of the number of vertices of the polytopes, for any d≥ 2. Expressing the Minkowski sum of the three polytopes as a section of their Cayley polytope C, the problem of counting the number of k-faces of P1+P2+P3, reduces to counting the number of (k+2)-faces of the subset of C comprising of the faces that contain at least one vertex from each Pi. In two dimensions our expressions reduce to known results, while in three dimensions, the tightness of our bounds follows by exploiting known tight bounds for the number of faces of r d-polytopes, where r≥ d. For d≥ 4, the maximum values are attained when P1, P2 and P3 are d-polytopes, whose vertex sets are chosen appropriately from three distinct d-dimensional moment-like curves.

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