Results 91 to 100 of about 219 (161)

Labeling regions in deformations of graphical arrangements

Combining Carver's variant of the Farkas' lemma with the Flow Decomposition Theorem we show that the regions of any deformation of a graphical arrangement may be bijectively labeled with a set of weighted digraphs containing directed cycles of negative ...
Hetyei, Gábor
core   +1 more source

Counting conjugacy classes of elements of finite order in exceptional Lie groups [PDF]

This paper continues the study of two numbers that are associated with Lie groups. The first number is \(N(G,m)\), the number of conjugacy classes of elements in \(G\) whose order divides \(m\).
Friedmann, Tamar, He, Qidong
core   +1 more source

Some theorems on the q-analogue of the generalized stirling numbers

, 2011
In this paper, we establish more properties for the q-analogue of the unied generalization of Stirling numbers including the vertical and horizontal recurrence relations, and the rational generating function.
Husna Zayadi
core  

Staircase patterns in words: subsequences, subwords, and separation number. [PDF]

Eur J Comb, 2020
Mansour T, Rastegar R, Roitershtein A.
europepmc   +1 more source

On the validations of the asymptotic matching conjectures

, 2020
In this paper we review the asymptotic matching conjectures for rregular bipartite graphs, and their connections in estimating the monomerdimer entropies in d-dimensional integer lattice and Bethe lattices.
S Friedland, E Krop, K Markström, P H Lundow   +3 more
core  

Enumeration of coalescent histories for caterpillar species trees and p-pseudocaterpillar gene trees. [PDF]

Adv Appl Math, 2021
Alimpiev E, Rosenberg NA.
europepmc   +1 more source

Alternating sign matrices with reflective symmetry and plane partitions: $n+3$ pairs of equivalent statistics and a Cauchy-type identity

Forum of Mathematics, Sigma
Vertically symmetric alternating sign matrices (VSASMs) of order $2n+1$ are known to be equinumerous with lozenge tilings of a hexagon with side lengths $2n+2,2n,2n+2,2n,2n+2,2n$ and a central triangular hole of size $2$ that exhibit
Ilse Fischer, Hans Höngesberg
doaj   +1 more source

A combinatorial proof of a result for permutation pairs

Open Mathematics, 2012
Mansour Toufik, Shattuck Mark
doaj   +1 more source

Permutations Which Are the Union of an Increasing and a Decreasing Subsequence

, 1998
It is shown that there are # 2n n # - # n-1 m=0 2 n-m-1 # 2m m # permutations which are the union of an increasing sequence and a decreasing sequence.
M. D. Atkinson
core  

The Bricklayer Problem And The Strong Cycle Lemma

, 1998
this paper, we solve a counting problem about building stacks of such blocks, which we call bricks. We have a linear base of length m on which we can place bricks. The bricks sitting directly on the base can start at any integer position, as long as they
Douglas B. West, Hunter S. Snevily
core