Sciweavers

JCT
2016
43views more  JCT 2016»
10 years 28 days ago
Almost-Fisher families
A classic theorem in combinatorial design theory is Fisher’s inequality, which states that a family F of subsets of [n] with all pairwise intersections of size λ can have at mo...
Shagnik Das, Benny Sudakov, Pedro Vieira
JCT
2016
47views more  JCT 2016»
10 years 28 days ago
Bipartite minors
We introduce a notion of bipartite minors and prove a bipartite analog of Wagner’s theorem: a bipartite graph is planar if and only if it does not contain K3,3 as a bipartite min...
Maria Chudnovsky, Gil Kalai, Eran Nevo, Isabella N...
JCT
2016
53views more  JCT 2016»
10 years 28 days ago
Littlewood-Richardson rules for symmetric skew quasisymmetric Schur functions
The classical Littlewood-Richardson rule is a rule for computing coefficients in many areas, and comes in many guises. In this paper we prove two Littlewood-Richardson rules for s...
Christine Bessenrodt, Vasu Tewari, Stephanie van W...
JCT
2016
327views more  JCT 2016»
10 years 28 days ago
Computing the partition function for graph homomorphisms with multiplicities
Abstract. We consider a refinement of the partition function of graph homomorphisms and present a quasi-polynomial algorithm to compute it in a certain domain. As a corollary, we ...
Alexander I. Barvinok, Pablo Soberón
JCT
2016
54views more  JCT 2016»
10 years 28 days ago
Double-dimers, the Ising model and the hexahedron recurrence
We define and study a recurrence relation in Z3 , called the hexahedron recurrence, which is similar to the octahedron recurrence (Hirota bilinear difference equation) and cube re...
Richard W. Kenyon, Robin Pemantle
JCT
2016
49views more  JCT 2016»
10 years 28 days ago
Certifying non-representability of matroids over prime fields
It is proved that, for a prime number p, showing that an n-element matroid is not representable over GF(p) requires only O(n2 ) rank evaluations.
Jim Geelen, Geoff Whittle
JCT
2016
46views more  JCT 2016»
10 years 28 days ago
The Newton polygon of a planar singular curve and its subdivision
Let a planar algebraic curve C be defined over a valuation field by an equation F(x, y) = 0. Valuations of the coefficients of F define a subdivision of the Newton polygon ∆ o...
Nikita Kalinin
JCT
2016
53views more  JCT 2016»
10 years 28 days ago
Diameter critical graphs
A graph is called diameter-k-critical if its diameter is k, and the removal of any edge strictly increases the diameter. In this paper, we prove several results related to a conje...
Po-Shen Loh, Jie Ma
JCT
2016
52views more  JCT 2016»
10 years 28 days ago
The anti-field-descent method
The essential fact behind the so-called field-descent method is that certain cyclotomic integers necessarily are contained in relatively small fields and thus must have relative...
Ka Hin Leung, Bernhard Schmidt