搜索结果: 16-30 共查到“知识库 组合数学”相关记录451条 . 查询时间(3.371 秒)
Every regular polytope has the remarkable property that it inherits all symmetries of each of its facets. This property distinguishes a natural class of polytopes which are called hereditary. Regular ...
Quivers with potentials associated to triangulated surfaces, part IV: Removing boundary assumptions
Quivers potentials triangulated surfaces Removing boundary assumptions Combinatorics
2012/6/30
We prove that the quivers with potentials associated by the author to ideal triangulations of punctured surfaces with empty boundary are non-degenerate, provided the number of punctures is 1 or greate...
Linear Programming Relaxations of Quadratically Constrained Quadratic Programs
Quadratic Programming Semidefinite Programming relaxation Linear Programming
2012/6/29
We investigate the use of linear programming tools for solving semidefinite programming relaxations of quadratically constrained quadratic problems. Classes of valid linear inequalities are presented,...
Intersection cuts from multiple rows: a disjunctive programming approach
Intersection cuts multiple rows disjunctive programming approach Combinatorics
2012/6/29
We address the issue of generating cutting planes for mixed integer programs from multiple rows of the simplex tableau with the tools of disjunctive programming. A cut from q rows of the simplex table...
Combined degree and connectivity conditions for H-linked graphs
Combined degree connectivity conditions H-linked graphs Combinatorics
2012/6/27
For a given multigraph H, a graph G is H-linked, if |G| \geq |H| and for every injective map {\tau}: V (H) \rightarrow V (G), we can find internally disjoint paths in G, such that every edge from uv i...
Lattice Point Generating Functions and Symmetric Cones
Lattice Point Generating Functions Symmetric Cones Combinatorics
2012/6/29
We show that a recent identity of Beck-Gessel-Lee-Savage on the generating function of symmetrically contrained compositions of integers generalizes naturally to a family of convex polyhedral cones th...
Constructing graphs with no immersion of large complete graphs
Graph immersion minimum degree chromatic number edgeconnectivity Hajos Conjecture Hadwiger Conjecture graph minor
2012/6/29
In 1989, Lescure and Meyniel proved, for $d=5, 6$, that every $d$-chromatic graph contains an immersion of $K_d$, and in 2003 Abu-Khzam and Langston conjectured that this holds for all $d$. In 2010, D...
Acyclic edge-coloring using entropy compression
Acyclic edge-coloring entropy compression Combinatorics
2012/6/29
An edge-coloring of a graph G is acyclic if it is a proper edge-coloring of G and every cycle contains at least three colors. We prove that every graph with maximum degree Delta has an acyclic edge-co...
Towards a weighted version of the Hajnal-Szemeredi Theorem
Towards a weighted version the Hajnal-Szemeredi Theorem Combinatorics
2012/6/27
For a positive integer r>=2, a K_r-factor of a graph is a collection vertex-disjoint copies of K_r which covers all the vertices of the given graph. The celebrated theorem of Hajnal and Szemer\'edi as...
Cycles and sorting index for matchings and restricted permutations
Cycles and sorting index matchings and restricted permutations Combinatorics
2012/6/25
We prove that the Mahonian-Stirling pairs of permutation statistics $(\sor, \cyc)$ and $(\inv, \mathrm{rlmin})$ are equidistributed on the set of permutations that correspond to arrangements of $n$ no...
The Minor inequalities in the description of the Set Covering Polyhedron of Circulant Matrices
polyhedral combinatorics set covering circulant matrices Combinatorics
2012/6/25
In this work we give a complete description of the set covering polyhedron of circulant matrices $C^k_{sk}$ with $s = 2,3$ and $k\geq 3 $ by linear inequalities. In particular, we prove that every non...
We prove that every claw-free graph $G$ that doesn't contain a clique on $\Delta(G) \geq 9$ vertices can be $\Delta(G) - 1$ colored.
Combinatorial study of colored Hurwitz polyzetas
Combinatorial study colored Hurwitz polyzetas Combinatorics
2012/6/25
A combinatorial study discloses two surjective morphisms between generalized shuffle algebras and algebras generated by the colored Hurwitz polyz\^etas. The combinatorial aspects of the products and c...
A new approach to the results of Kovari, Sos, and Turan concerning rectangle-free subsets of the grid
Turan concerning rectangle-free subsets of the grid Combinatorics
2012/6/21
For positive integers $m$ and $n$, define $f(m,n)$ to be the smallest integer such that any subset $A$ of the $m \times n$ integer grid with $|A| \geq f(m,n)$ contains a rectangle; that is, there are ...
Permutations all of whose patterns of a given length are distinct
Permutations a given length distinct Combinatorics
2012/6/21
For each integer k >= 2, let F(k) denote the largest n for which there exists a permutation \sigma \in S_n, all of whose patterns of length k are distinct. We prove that F(k) = k + \lfloor \sqrt{2k-3}...