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CPC
2008
86views more  CPC 2008»
13 years 2 months ago
Enumeration Schemes for Restricted Permutations
Abstract. Zeilberger's enumeration schemes can be used to completely automate the enumeration of many permutation classes. We extend his enumeration schemes so that they apply...
Vincent Vatter
DM
1999
96views more  DM 1999»
13 years 3 months ago
Buekenhout unitals
The only known enumeration of Buekenhout unitals occurs in the Desarguesian plane PG(2, q2). In this paper we develop general techniques for enumerating the nonsingular Buekenhout...
Gary L. Ebert
COMBINATORICS
2002
87views more  COMBINATORICS 2002»
13 years 3 months ago
Kasteleyn Cokernels
We consider Kasteleyn and Kasteleyn-Percus matrices, which arise in enumerating matchings of planar graphs, up to matrix operations on their rows and columns. If such a matrix is ...
Greg Kuperberg
COMBINATORICS
2004
112views more  COMBINATORICS 2004»
13 years 3 months ago
Airy Phenomena and Analytic Combinatorics of Connected Graphs
Until now, the enumeration of connected graphs has been dealt with by probabilistic methods, by special combinatorial decompositions or by somewhat indirect formal series manipula...
Philippe Flajolet, Bruno Salvy, Gilles Schaeffer
JQL
2006
75views more  JQL 2006»
13 years 3 months ago
Improving calculations of the number of distinct alignments of two strings
In a recent work, M. Covington discusses the enumeration of two different sets of alignments of two strings of symbols using elementary combinatorial techniques. He defines two fu...
Øystein J. Rødseth, James A. Sellers
ARSCOM
2008
117views more  ARSCOM 2008»
13 years 3 months ago
Subset Counting in Trees
Various enumeration problems for classes of simply generated families of trees have been the object of investigation in the past. We mention the enumeration of independent subsets,...
Stephan G. Wagner
AML
2010
80views more  AML 2010»
13 years 3 months ago
Goodness in the enumeration and singleton degrees
We investigate and extend the notion of a good approximation with respect to the enumeration (De) and singleton (Ds) degrees. We refine two results by Griffith, on the inversion of...
Charles M. Harris