Báo cáo toán học: "A simple proof for the existence of exponentially balanced Gray codes" ppsx

Báo cáo toán học: " A NEW CONSTRUCTION FOR CANCELLATIVE FAMILIES OF SETS" doc

Báo cáo toán học: " A NEW CONSTRUCTION FOR CANCELLATIVE FAMILIES OF SETS" doc

... the union of any element of F 1 with any element of F 2 . It is easy to see that the product of two cancellative families is also a cancellative family ( (A 1 ,A 2 ) ∪(B 1 ,B 2 )= (A 1 ,A 2 ) ∪(C 1 ,C 2 ) ... ask how large cancellative families can be. We define f(n) to be the size of the largest possible cancellative family of subsets of a n-set and f(k,n)...
Ngày tải lên : 07/08/2014, 06:20
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Báo cáo toán học: "A Simple Method for Constructing Small Cubic Graphs of Girths 14, 15, and 16" pptx

Báo cáo toán học: "A Simple Method for Constructing Small Cubic Graphs of Girths 14, 15, and 16" pptx

... 1996 Abstract A method for constructing cubic graphs with girths in the range 13 to 16 is described. The method is used to construct the smallest known cubic graphs for girths 14, 15 and 16. Introduction We ... JournalofGraphTheory,6, 1982, 1-22. A Simple Method for Constructing Small Cubic Graphs of Girths 14, 15, and 16 Geoffrey Exoo Departm...
Ngày tải lên : 07/08/2014, 06:20
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Báo cáo toán học: "A simple algorithm for constructing Szemer´di’s Regularity Partition e" pps

Báo cáo toán học: "A simple algorithm for constructing Szemer´di’s Regularity Partition e" pps

... A simple algorithm for constructing Szemer´edi’s Regularity Partition Alan Frieze Department of Mathematical Sciences, Carnegie ... combinatorics 6 (1999), #R17 3 A partition satisfying the second criterion is called equitable. V 0 is called the exceptional class. Following [9], for every equitable partition P into k +1classes ... (ˆx + ) T Wˆy − ≥ ˆγ √ pq/4. (The proof for...
Ngày tải lên : 07/08/2014, 06:20
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Báo cáo toán học: "A construction method for complete sets of mutually orthogonal frequency squares" pdf

Báo cáo toán học: "A construction method for complete sets of mutually orthogonal frequency squares" pdf

... survey of frequency squares. A set of (n − 1) 2 /(m − 1) mutually orthogonal frequency squares (MOFS) of type F (n; λ)isacomplete set of type F (n; λ). We shall describe a construction for complete ... 2000. Abstract A construction is described for combining affine designs with complete sets of mutually orthogonal frequency squares to produce other complet...
Ngày tải lên : 07/08/2014, 06:20
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Báo cáo toán học: "An Asymptotic Expansion for the Number of Permutations with a Certain Number of Inversions" docx

Báo cáo toán học: "An Asymptotic Expansion for the Number of Permutations with a Certain Number of Inversions" docx

... referee for numerous comments and suggestions which have led to a substantially improved paper. An Asymptotic Expansion for the Number of Permutations with a Certain Number of Inversions Lane Clark Department ... Eds., Handbook of Mathematical Functions with Formulas, Graphs and Mathematical Tables, Dover Publications, New York, 1966. [2] E .A. Bender, Central...
Ngày tải lên : 07/08/2014, 06:20
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Báo cáo toán học: "A LOWER BOUND FOR THE NUMBER OF EDGES IN A GRAPH CONTAINING NO TWO CYCLES OF THE SAME LENGTH" pptx

Báo cáo toán học: "A LOWER BOUND FOR THE NUMBER OF EDGES IN A GRAPH CONTAINING NO TWO CYCLES OF THE SAME LENGTH" pptx

... v(G) denote the number of vertices, and (G) denote the number of edges. In this paper, we construct a graph G having no two cycles with the same length which leads to the following result. Theorem. ... Chunhui Lai, On the size of graphs with all cycle having distinct length, Discrete Math. 122(1993) 363-364. [6] Chunhui Lai, The edges in a graph...
Ngày tải lên : 07/08/2014, 06:22
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Báo cáo toán học: "A simple proof for the existence of exponentially balanced Gray codes" ppsx

Báo cáo toán học: "A simple proof for the existence of exponentially balanced Gray codes" ppsx

... is the number of times the integer i occurs in the sequence T . Note that the sum of all b(i), 1 ≤ i ≤ n,isequaltol, the length of T . 3 A simple proof for the existence of exponentially balanced ... two, or are two successive powers of two. A proof for the existence of exponentially balanced Gray codes is derived. The proof is much sim- p...
Ngày tải lên : 07/08/2014, 08:22
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Báo cáo toán học: "A Simple Proof of the Aztec Diamond Theorem" potx

Báo cáo toán học: "A Simple Proof of the Aztec Diamond Theorem" potx

... 1986. the electronic journal of combinatorics 12 (2005), #R18 8 Theorem 2.3 (Aztec diamond theorem) The number of domino tilings of the Aztec diamond of order n is 2 n(n+1)/2 . Remark: The proof of ... between domino tilings of an Aztec diamond and non- intersecting lattice paths, a simple proof of the Aztec diamond theorem is given by means of...
Ngày tải lên : 07/08/2014, 08:22
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Báo cáo toán học: "A sharp bound for the reconstruction of partitions" ppt

Báo cáo toán học: "A sharp bound for the reconstruction of partitions" ppt

... agree above row r and to the left of column c (and the definitions of r and c) we see that the only possibility for /à is (r, c), completing the proof of this case and the theorem. Acknowledgements. ... 308, 9 (2008), 1524–1530. the electronic journal of combinatorics 15 (2008), #N23 4 A sharp bound for the reconstruction of partitions Vincent Vatter Departme...
Ngày tải lên : 07/08/2014, 15:22
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Báo cáo toán học: "A closed formula for the number of convex permutominoes" pot

Báo cáo toán học: "A closed formula for the number of convex permutominoes" pot

... interpretation of the closed formula (10) for the number of con- vex permutominoes. We remark that the expression of f n resembles the expression (1) for the number c n of convex polyominoes of semi-perimeter ... : the uppermost cell of the rightmost column of the polyomino has the maximal ordinate among all the cells of the polyomino; U2 :...
Ngày tải lên : 07/08/2014, 15:22
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Báo cáo toán học: "A natural series for the natural logarithm" pot

Báo cáo toán học: "A natural series for the natural logarithm" pot

... that those formulae yield interesting power series expansions for the logarithm function. This generalizes an infinite series of Lehmer for the natural logarithm of 4. 1 The abelian case: the Mahler ... fundamental group of the knot complement. For a square matrix M with entries in CG the trace tr CG (M) denotes the coefficient of the unit element in the sum of the...
Ngày tải lên : 07/08/2014, 15:23
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Báo cáo toán học: "A normalization formula for the Jack polynomials in superspace and an identity on partitions" pps

Báo cáo toán học: "A normalization formula for the Jack polynomials in superspace and an identity on partitions" pps

... b i in P [k] j,i . the electronic journal of combinatorics 16 (2009), #R70 18 A normalization formula for the Jack polynomials in superspace and an identity on partitions Luc Lapointe ∗ Instituto ... where σ j and ∂ j are respectively the interchang e and divided difference operators on the variables a j and a j+1 (see for instance [6]). The main st...
Ngày tải lên : 07/08/2014, 21:21
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Báo cáo toán học: "A Colorful Involution for the Generating Function for Signed Stirling Numbers of the First Kind" pps

Báo cáo toán học: "A Colorful Involution for the Generating Function for Signed Stirling Numbers of the First Kind" pps

... Beissinger, who was the first to explore [1] combinatorial proofs using colored permutations, for their assistance. References [1] Janet Beissinger. Colorful proofs of generating function identities. ... follows for (π, f ) ∈ S n,A : If R (π,f) = ∅, let φ((π, f)) = (π, f). Otherwise, let (i, j) ∈ R (π,f) be minimal under the lexicographic ordering of R (π,f) . Let ˜π = (i, j)...
Ngày tải lên : 08/08/2014, 01:20
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Báo cáo toán học: "A recurrence relation for the “inv” analogue of q-Eulerian polynomials" ppsx

Báo cáo toán học: "A recurrence relation for the “inv” analogue of q-Eulerian polynomials" ppsx

... A recurrence relation for the “inv” analogue of q-Eulerian polynomials Chak-On Chow Department of Mathematics and Information Technology, Hong Kong Institute of Education, 10 Lo ... relation algebraically. In the final section, we give a combinatorial proof of this recurrence relation. 2 The recurrence relation We derive in the present section the rec...
Ngày tải lên : 08/08/2014, 11:20
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Báo cáo toán học: "A short proof for the number of permutations containing pattern 321 exactly once" ppt

Báo cáo toán học: "A short proof for the number of permutations containing pattern 321 exactly once" ppt

... a short proof for the result of Noonan [3] that the number of permutations of length n containing exactly one occurence of pattern 321 is 3 n  2n n−3  . (To be precise, Noonan considered permutations ... A short proof for the number of permutations containing pattern 321 exactly once Alexander Burstein Department of Mathematics Howard...
Ngày tải lên : 08/08/2014, 14:23
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