학술논문

Enumeration of walks in the square lattice according to their areas.
Document Type
Journal
Author
Mohammad-Noori, M. (IR-TEH-MSC) AMS Author Profile
Source
Journal of Combinatorial Mathematics and Combinatorial Computing (J. Combin. Math. Combin. Comput.) (20140101), 91, 257-274. ISSN: 0835-3026 (print).eISSN: 2817-576X.
Subject
05 Combinatorics -- 05A Enumerative combinatorics
  05A15 Exact enumeration problems, generating functions
Language
English
Abstract
Summary: ``We study the area distribution of closed walks of length $n$, starting and ending at the origin. The concept of algebraic area of a walk in the square lattice is slightly modified and the usefulness of this concept is demonstrated through a simple argument. The idea of using a generating function of the form $(x+x^{-1}+y+y^{-1})^n$ to study these walks is then discussed from a special viewpoint. Based on this, a polynomial time algorithm for calculating the exact distribution of such walks for a given length, is concluded. The presented algorithm takes advantage of the Chinese remainder theorem to overcome the problem of arithmetic with large integers. Finally, the results of the implementation are given for $n=32, 64, 128$.''

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