Báo cáo toán học: "Orthogonal art galleries with holes: a coloring proof of Aggarwal’s Theorem" potx

... resultant quadrilateralization graph. Let us recall that a quadrilateralization of an orthogonal polygon P (with or without holes) is a partitioning of P into a set of convex quadrilaterals with pairwise ... Orthogonal galleries with one hole Let Q be a quadrilateralization of an n-vertex orthogonal polygon P with one hole. By adding both diagonals to each quadrilater...

Ngày tải lên: 07/08/2014, 13:21

... journal of combinatorics 11 (2004), #R62 3 Random Cayley graphs are expanders: a simple proof of the Alon–Roichman theorem ZEPH LANDAU Department of Mathematics City College of New York landau@sci.ccny.cuny.edu A LEXANDER ... adjacency matrix of the graph is less than ε as long as k ≥ (c ε + o(1)) log |G|. Their proof involves a clever combinatorial argument that controls...

Ngày tải lên: 07/08/2014, 08:20

... described each of the arrays A s as endowing N 0 with the algebraic structure of a quasigroup [22]. We discuss results related to this algebraic approach in [1]; that article deals with the same family ... operation of Nim- addition. In particular, these arrays display periodic behavior along rows and diagonals. We explain how various features of computer-generated graphics de...

Ngày tải lên: 08/08/2014, 12:22

... from a set S that contains s symbols is said to be an orthogonal array with s levels, strength t and index λ if every N ×t subarray of A contains ∗ Osaka prefectual Nagano high school, 1-1-2 Hara, ... Hara, Kawachinagano, Osaka, Japan, e-mail; denen482@yahoo.co .jp the electronic journal of combinatorics 18 (2011), #P69 1 PROOF. From Lemmas A, B, C and the theorem of Veblen and...

Ngày tải lên: 08/08/2014, 14:22

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Ngày tải lên: 05/08/2014, 15:21