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COMBINATORICS
2006
15 years 3 months ago
2006
In this paper, we consider matchings avoiding partial patterns 1123 and 1132. We give a bijection between 1123-avoiding matchings with n edges and nonnegative lattice paths from (...
112
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COMBINATORICS
2006
15 years 3 months ago
2006
A differential poset is a partially ordered set with raising and lowering operators U and D which satisfy the commutation relation DU-UD = rI for some constant r. This notion may ...
128
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COMBINATORICS
2006
15 years 3 months ago
2006
We give a parity reversing involution on noncrossing trees that leads to a combinatorial interpretation of a formula on noncrossing trees and symmetric ternary trees in answer to a...
109
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COMBINATORICS
2006
15 years 3 months ago
2006
It is proved that, if G is a K4-minor-free graph with maximum degree 4, then G is totally ( + 1)-choosable; that is, if every element (vertex or edge) of G is assigned a list of ...
143
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COMBINATORICS
2006
15 years 3 months ago
2006
A "hybrid method", dedicated to asymptotic coefficient extraction in combinatorial generating functions, is presented, which combines Darboux's method and singulari...