Title
The number of Z-convex polyominoes
Abstract
In this paper we consider a restricted class of polyominoes that we call Z-convex polyominoes. Z-convex polyominoes are polyominoes such that any two pairs of cells can be connected by a monotone path making at most two turns (like the letter Z). This class of convex polyominoes appears to resist standard decompositions, so we propose a construction by ''inflation'' that allows to write a system of functional equations for their generating functions. The generating function P(t) of Z-convex polyominoes with respect to the semi-perimeter turns out to be algebraic all the same and surprisingly, like the generating function of convex polyominoes, it can be expressed as a rational function of t and the generating function of Catalan numbers.
Year
DOI
Venue
2008
10.1016/j.aam.2006.07.004
Advances in Applied Mathematics
Keywords
Field
DocType
functional equation,catalan number,. enumeration,generating function,monotone path,z-convex polyominoes,recursive decomposition. the authors acknowledge support from the french anr under the sada project.,algebraic generating functions,restricted class,generating function p,rational function,letter z,convex polyominoes,primary,enumeration
Discrete mathematics,Generating function,Combinatorics,Algebraic number,Mathematical analysis,Polyomino,Catalan number,Convex function,Rational function,Functional equation,Monotone polygon,Mathematics
Journal
Volume
Issue
ISSN
40
1
0196-8858
Citations 
PageRank 
References 
12
0.90
9
Authors
3
Name
Order
Citations
PageRank
Enrica Duchi14916.21
Simone Rinaldi217424.93
Gilles Schaeffer342344.82