Results 41 to 50 of about 16,950 (147)

A Polynomial-time Algorithm for Outerplanar Diameter Improvement

, 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, Gonçalves, Daniel, Kim, Eun Jung, Paul, Christophe, Sau, Ignasi, Thilikos, Dimitrios M., Weller, Mathias   +6 more
core   +3 more sources

Reconstruction of maximal outerplanar graphs

Discrete Mathematics, 1972
AbstractS. Ulam has conjectured that every graph with three or more points is uniquely determined by its collection of point-deleted subgraphs. This has been proved for various classes of graphs, but progress has generally been confined to very symmetrical graphs and graphs with connectivity zero or one.
openaire   +2 more sources

On the Fiedler value of large planar graphs [PDF]

, 2013
The Fiedler value $\lambda_2$, also known as algebraic connectivity, is the second smallest Laplacian eigenvalue of a graph. We study the maximum Fiedler value among all planar graphs $G$ with $n$ vertices, denoted by $\lambda_{2\max}$, and we show the ...
Alon, Barrière, Biswal, Brouwer, Clemens Huemer, David Orden, de Abreu, Dieter Mitsche, Elsner, Fiedler, Freitas, Gilbert, Kawarabayashi, Kelner, Kelner, Koebe, Lali Barrière, Merris, Mohar, Mohar, Molitierno, Nešetřil, Song, Spielman, Spielman, Thomason   +25 more
core   +4 more sources

Face Sizes and the Connectivity of the Dual

Journal 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, Kenta Noguchi, Heidi Van den Camp   +2 more
wiley   +1 more source

Strongly Monotone Drawings of Planar Graphs [PDF]

, 2016
A straight-line drawing of a graph is a monotone drawing if for each pair of vertices there is a path which is monotonically increasing in some direction, and it is called a strongly monotone drawing if the direction of monotonicity is given by the ...
Felsner, Stefan, Igamberdiev, Alexander, Kindermann, Philipp, Klemz, Boris, Mchedlidze, Tamara, Scheucher, Manfred   +5 more
core   +2 more sources

Recognizing Trees From Incomplete Decks

Journal 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

A Survey of Maximal k-Degenerate Graphs and k-Trees

Theory and Applications of Graphs
This article surveys results on maximal $k$-degenerate graphs, $k$-trees, and related classes including simple $k$-trees, $k$-paths, maximal outerplanar graphs, and Apollonian networks.
Allan Bickle
doaj   +1 more source

On reconstructing maximal outerplanar graphs

Discrete Mathematics, 1974
Manvel has proved that a maximal outerplanar graph can be reconstructed from the collection of isomorphism types of subgraphs obtained by deleting vertices of the given graph. This paper sharpens Manvel's result by showing that if the graph is not a triangulation of a hexagon, then reconstruction can be accomplished using only those isomorphism types ...
openaire   +1 more source

On Endomorphism Universality of Sparse Graph Classes

Journal 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

Feedback Arc Number and Feedback Vertex Number of Cartesian Product of Directed Cycles

Discrete Dynamics in Nature and Society, Volume 2019, Issue 1, 2019., 2019
For a digraph D, the feedback vertex number τ(D), (resp. the feedback arc number τ′(D)) is the minimum number of vertices, (resp. arcs) whose removal leaves the resultant digraph free of directed cycles. In this note, we determine τ(D) and τ′(D) for the Cartesian product of directed cycles D=Cn1→□Cn2→□…Cnk→. Actually, it is shown that τ′D=n1n2…nk∑i=1k1/
Xiaohong Chen, Baoyindureng Wu, Seenith Sivasundaram   +2 more
wiley   +1 more source