scholarly journals Some results for directed lattice walkers in a strip

2003 ◽  
Vol DMTCS Proceedings vol. AC,... (Proceedings) ◽  
Author(s):  
Yao-Ban Chan ◽  
Anthony J. Guttmann
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Finite Width ◽  
Horizontal Strip ◽  
Growth Constant ◽  
Vicious Walkers ◽  
Small Width ◽  
International Audience

International audience Using a transfer matrix method, we present some results for directed lattice walkers in a horizontal strip of finite width. Some cases with two walkers in a small width are solved exactly, as are a couple of cases with vicious walkers in a small width; a conjecture is made for a case with three walkers. We also derive the general transfer matrix for two walkers. Lastly, we examine the dependence of the growth constant on the width and friendliness.

scholarly journals Partition and composition matrices: two matrix analogues of set partitions

2011 ◽  
Vol DMTCS Proceedings vol. AO,... (Proceedings) ◽  
Author(s):  
Anders Claesson ◽  
Mark Dukes ◽  
Martina Kubitzke
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Set Partitions ◽  
Nous Montrons ◽  
International Audience ◽  
One To One ◽  
Natural Result ◽  
Ascent Sequences ◽  
Nous Utilisons

International audience This paper introduces two matrix analogues for set partitions; partition and composition matrices. These two analogues are the natural result of lifting the mapping between ascent sequences and integer matrices given in Dukes & Parviainen (2010). We prove that partition matrices are in one-to-one correspondence with inversion tables. Non-decreasing inversion tables are shown to correspond to partition matrices with a row ordering relation. Partition matrices which are s-diagonal are classified in terms of inversion tables. Bidiagonal partition matrices are enumerated using the transfer-matrix method and are equinumerous with permutations which are sortable by two pop-stacks in parallel. We show that composition matrices on the set $X$ are in one-to-one correspondence with (2+2)-free posets on $X$.We show that pairs of ascent sequences and permutations are in one-to-one correspondence with (2+2)-free posets whose elements are the cycles of a permutation, and use this relation to give an expression for the number of (2+2)-free posets on $\{1,\ldots,n\}$. Ce papier introduit deux analogues matriciels des partitions d'ensembles: les matrices de composition et de partition. Ces deux analogues sont le produit naturel du relèvement de l'application entre suites de montées et matrices d'entiers introduite dans Dukes & Parviainen (2010). Nous démontrons que les matrices de partition sont en bijection avec les tables d'inversion, les tables d'inversion croissantes correspondant aux matrices de partition avec une relation d'ordre sur les lignes. Les matrices de partition s-diagonales sont classées en fonction de leurs tables d'inversion. Les matrices de partition bidiagonales sont énumérées par la méthode de matrices de transfert et ont même cardinalité que les permutations triables par deux piles en parallèle. Nous montrons que les matrices de composition sur l'ensemble $X$ sont en bijection avec les ensembles ordonnés (2+2)-libres sur $X$. Nous prouvons que les paires de suites de montées et de permutations sont en bijection avec les ensembles ordonnés (2+2)-libres dont les éléments sont les cycles d'une permutation, et nous utilisons cette relation pour exprimer le nombre d'ensembles ordonnés (2+2)-libres sur $\{1,\ldots,n\}$.

scholarly journals Computing generating functions of ordered partitions with the transfer-matrix method

2006 ◽  
Vol DMTCS Proceedings vol. AG,... (Proceedings) ◽  
Author(s):  
Masao Ishikawa ◽  
Anisse Kasraoui ◽  
Jiang Zeng
Keyword(s):  
Transfer Matrix ◽  
Generating Function ◽  
Generating Functions ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Stirling Number ◽  
International Audience

International audience An ordered partition of $[n]:=\{1,2,\ldots, n\}$ is a sequence of disjoint and nonempty subsets, called blocks, whose union is $[n]$. The aim of this paper is to compute some generating functions of ordered partitions by the transfer-matrix method. In particular, we prove several conjectures of Steingrímsson, which assert that the generating function of some statistics of ordered partitions give rise to a natural $q$-analogue of $k!S(n,k)$, where $S(n,k)$ is the Stirling number of the second kind.

scholarly journals Counting Polyominoes on Twisted Cylinders

2005 ◽  
Vol DMTCS Proceedings vol. AE,... (Proceedings) ◽  
Author(s):  
Gill Barequet ◽  
Micha Moffie ◽  
Ares Ribó ◽  
Günter Rote
Keyword(s):  
Growth Rate ◽  
Transfer Matrix ◽  
Lower Bounds ◽  
Exponential Growth ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Compact Representation ◽  
Exponential Growth Rate ◽  
Successive Iteration ◽  
International Audience

International audience We improve the lower bounds on Klarner's constant, which describes the exponential growth rate of the number of polyominoes (connected subsets of grid squares) with a given number of squares. We achieve this by analyzing polyominoes on a different surface, a so-called $\textit{twisted cylinder}$ by the transfer matrix method. A bijective representation of the "states'' of partial solutions is crucial for allowing a compact representation of the successive iteration vectors for the transfer matrix method.

A Finite-Width Crack Model for Rotor Dynamic Analysis by Transfer Matrix Method

2006 ◽  
Vol 324-325 ◽  
pp. 1003-1006
Author(s):  
Ke Ming Wang ◽  
Song Xiang
Keyword(s):  
Dynamic Analysis ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Transverse Crack ◽  
Rotor System ◽  
Crack Model ◽  
Finite Width ◽  
Stiffness Reduction ◽  
Rotor Dynamic

Understanding dynamic behavior of a rotor system with a transverse crack is of great significance for operation reliability of rotating machinery. The transfer matrix method is widely used for rotor dynamic analysis, but it encounters difficulties modeling a crack. This study proposes a finite-width crack model that simulates the local stiffness reduction effect of a gaping crack in transfer matrix method. This model is obtained by comparing finite element analysis results of a shaft with a zero-width crack and its counterpart transfer matrix calculation results with a trial equivalent finite-width slot. Different shaft geometry and loading modes are considered to improve the generality of the model. An application example is given that uses the proposed model to calculate critical speeds of a multi-disk rotor system with a transverse crack at different positions.

Adaptable transfer-matrix method for fixed-energy finite-width beams

2021 ◽  
Vol 96 (3) ◽  
pp. 035220
Author(s):  
A Bernal ◽  
J Avendaño ◽  
R Valencia-Torres ◽  
J García-Ravelo
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Finite Width ◽  
Fixed Energy
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