Results 81 to 90 of about 132,418 (291)

A bijection for plane graphs and its applications

open access: yesWorkshop on Analytic Algorithmics and Combinatorics, 2014
This paper is concerned with the counting and random sampling of plane graphs (simple planar graphs embedded in the plane). Our main result is a bijection between the class of plane graphs with triangular outer face, and a class of oriented binary trees.
O. Bernardi, Gwendal Collet, Éric Fusy
semanticscholar   +1 more source

Two bijections on Tamari Intervals [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2014
We use a recently introduced combinatorial object, the $\textit{interval-poset}$, to describe two bijections on intervals of the Tamari lattice. Both bijections give a combinatorial proof of some previously known results. The first one is an inner bijection between Tamari intervals that exchanges the $\textit{initial rise}$ and $\textit{lower contacts}$
Chapoton, Frédéric   +2 more
openaire   +4 more sources

Enumeration of E(s2) $\,E({s}^{2})$‐Optimal and Minimax‐Optimal Supersaturated Designs With 12 Rows, 11q $11q$ Columns and smax=4 ${s}_{{\rm{\max }}}=4$

open access: yesJournal of Combinatorial Designs, EarlyView.
ABSTRACT The E(s2) $\,E({s}^{2})$‐optimal and minimax‐optimal supersaturated designs (SSDs) with 12 rows, 11q $11q$ columns, and smax=4 ${s}_{{\rm{\max }}}=4$ are enumerated in a computer search: there are, respectively, 34, 146, 0, 3, and 1 such designs for q=2,3,4,5 $q=2,3,4,5$, and 6.
Luis B. Morales
wiley   +1 more source

Enumeration of Corners in Tree-like Tableaux [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2016
In this paper, we confirm conjectures of Laborde-Zubieta on the enumeration of corners in tree-like tableaux and in symmetric tree-like tableaux. In the process, we also enumerate corners in (type $B$) permutation tableaux and (symmetric) alternative ...
Alice L. L. Gao   +3 more
doaj   +1 more source

On Endomorphism Universality of Sparse Graph Classes

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT We show that every commutative idempotent monoid (a.k.a. lattice) is the endomorphism monoid of a subcubic graph. This solves a problem of Babai and Pultr and the degree bound is best‐possible. On the other hand, we show that no class excluding a minor can have all commutative idempotent monoids among its endomorphism monoids. As a by‐product,
Kolja Knauer, Gil Puig i Surroca
wiley   +1 more source

Operators of equivalent sorting power and related Wilf-equivalences [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2013
We study sorting operators $\textrm{A}$ on permutations that are obtained composing Knuth's stack sorting operator \textrmS and the reverse operator $\textrm{R}$, as many times as desired.
Michael Albert, Mathilde Bouvel
doaj   +1 more source

Bijections for partition identities

open access: yesJournal of Combinatorial Theory, Series A, 1988
AbstractWe consider partition-identity bijections that can be constructed from sieve-equivalent families whose defining multisets are pairwise disjoint. We give a linear algorithm that constructs these bijections. We show that under these conditions, the new algorithm, the Garsia-Milne-Remmel algorithm, and the Gordon algorithm are equivalent, i.e ...
openaire   +2 more sources

Precedence‐Constrained Shortest Path

open access: yesNetworks, EarlyView.
ABSTRACT We propose a variant of the shortest path problem where the order in which vertices occur in the path is subject to precedence constraints. Precedence constraints are defined in terms of vertex pairs (a,b)$$ \left(a,b\right) $$ which indicate that a vertex a$$ a $$ is the predecessor of a vertex b$$ b $$.
Christina Büsing   +2 more
wiley   +1 more source

Resources for Research on Analogy: A Multi-disciplinary Guide

open access: yesInformal Logic, 2009
Work on analogy has been done from a number of disciplinary perspectives throughout the history of Western thought. This work is a multidisciplinary guide to theorizing about analogy.
Marcello Guarini   +3 more
doaj   +1 more source

A bijection between irreducible k-shapes and surjective pistols of height $k-1$ [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2014
This paper constructs a bijection between irreducible $k$-shapes and surjective pistols of height $k-1$, which carries the "free $k$-sites" to the fixed points of surjective pistols.
Ange Bigeni
doaj   +1 more source

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