Counting partially directed walks in a symmetric wedge

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Description: Prellberg, T (QMUL)
Friday 11 April 2008, 14:15-15:00
Combinatorial Identities and their Applications in Statistical Mechanics
 
Created: 2008-04-29 11:26
Collection: Combinatorics and Statistical Mechanics
Publisher: Isaac Newton Institute
Copyright: Prellberg, T
Language: eng (English)
Distribution: World     (downloadable)
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Author:  Prellberg, T
Explicit content: No
Aspect Ratio: 4:3
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Bumper: /sms-ingest/static/new-4x3-bumper.dv
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Abstract: The enumeration of lattice paths in wedges poses unique mathematical challenges. These models are not translationally invariant, and the absence of this symmetry complicates both the derivation of a functional recurrence for the generating function, and its solution.

We consider a model of partially directed walks from the origin in the square lattice confined to a symmetric wedge defined by Y = ±X.

We derive a functional equation for the generating function of the model, and obtain an explicit solution using a version of the Kernel method.

This solution shows that there is a direct connection with matchings of an 2n-set counted with respect to the number of crossings, and a bijective proof has since been obtained.

Related Links
* http://www.maths.qmul.ac.uk/~tp/papers/pub057.pdf - Partially directed paths in a wedge (van Rensburg; Prellberg; Rechnitzer)
* http://arxiv.org/abs/0712.2804v3 - Nestings of Matchings and Permutations and North Steps in PDSAWs (Rubey)
* http://arxiv.org/abs/0803.4233v1 - A Bijection Between Partially Directed Paths in the Symmetric Wedge and Matchings (Poznanovik)
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