Results 51 to 60 of about 3,997 (179)

Frequent Subgraph Mining in Outerplanar Graphs [PDF]

open access: yes, 2010
In recent years there has been an increased interest in frequent pattern discovery in large databases of graph structured objects. While the frequent connected subgraph mining problem for tree datasets can be solved in incremental polynomial time, it ...
Horvath, Tamas   +2 more
core   +1 more source

A Polynomial-time Algorithm for Outerplanar Diameter Improvement

open access: yes, 2014
The Outerplanar Diameter Improvement problem asks, given a graph $G$ and an integer $D$, whether it is possible to add edges to $G$ in a way that the resulting graph is outerplanar and has diameter at most $D$.
Cohen, Nathann   +6 more
core   +3 more sources

Face Sizes and the Connectivity of the Dual

open access: yesJournal of Graph Theory, Volume 110, Issue 4, Page 379-391, December 2025.
ABSTRACT For each c ≥ 1, we prove tight lower bounds on face sizes that must be present to allow 1‐ or 2‐cuts in simple duals of c‐connected maps. Using these bounds, we determine the smallest genus on which a c‐connected map can have a simple dual with a 2‐cut and give lower and some upper bounds for the smallest genus on which a c‐connected map can ...
Gunnar Brinkmann   +2 more
wiley   +1 more source

L(2, 1)-Labelings of Some Families of Oriented Planar Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2014
In this paper we determine, or give lower and upper bounds on, the 2-dipath and oriented L(2, 1)-span of the family of planar graphs, planar graphs with girth 5, 11, 16, partial k-trees, outerplanar graphs and cacti.
Sen Sagnik
doaj   +1 more source

Alpha Labeling of Amalgamated Cycles

open access: yesTheory and Applications of Graphs, 2022
A graceful labeling of a bipartite graph is an \a-labeling if it has the property that the labels assigned to the vertices of one stable set of the graph are smaller than the labels assigned to the vertices of the other stable set.
Christian Barrientos
doaj   +1 more source

Recognizing Trees From Incomplete Decks

open access: yesJournal of Graph Theory, Volume 110, Issue 3, Page 322-336, November 2025.
ABSTRACT Given a graph G, the unlabeled subgraphs G − v are called the cards of G. The deck of G is the multiset { G − v : v ∈ V ( G ) }. Wendy Myrvold showed that a disconnected graph and a connected graph both on n vertices have at most ⌊ n 2 ⌋ + 1 cards in common and found (infinite) families of trees and disconnected forests for which this upper ...
Gabriëlle Zwaneveld
wiley   +1 more source

Outerplanar Graphs and Delaunay Triangulations [PDF]

open access: yes, 2012
Dillencourt [1] showed that all maximal outerplanar graphs can be realized as Delaunay triangulations of points in convex position. In this note, we give two new, alternate proofs.
Alam, Ashraful   +2 more
openaire   +2 more sources

To Prove Four Color Theorem [PDF]

open access: yes, 2016
In this paper, we give a proof for four color theorem(four color conjecture). Our proof does not involve computer assistance and the most important is that it can be generalized to prove Hadwiger Conjecture. Moreover, we give algorithms to color and test
Cao, Weiwei, Yue, Weiya
core  

Small Superpatterns for Dominance Drawing

open access: yes, 2013
We exploit the connection between dominance drawings of directed acyclic graphs and permutations, in both directions, to provide improved bounds on the size of universal point sets for certain types of dominance drawing and on superpatterns for certain ...
Bannister, Michael J.   +2 more
core   +1 more source

On Endomorphism Universality of Sparse Graph Classes

open access: yesJournal of Graph Theory, Volume 110, Issue 2, Page 223-244, October 2025.
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

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