Clique-Width for Four-Vertex Forbidden Subgraphs

2005 ◽  
pp. 185-196
Author(s):  
Andreas Brandstädt ◽  
Joost Engelfriet ◽  
Hoàng-Oanh Le ◽  
Vadim V. Lozin
Keyword(s):  
Forbidden Subgraphs

scholarly journals Toughness, Forbidden Subgraphs and Pancyclicity

2021 ◽  
Vol 37 (3) ◽  
pp. 839-866
Author(s):  
Wei Zheng ◽  
Hajo Broersma ◽  
Ligong Wang
Keyword(s):  
Recent Article ◽  
Forbidden Subgraph ◽  
Forbidden Subgraphs ◽  
Free Graph ◽  
Induced Subgraph ◽  
Complete Answer ◽  
Open Case

AbstractMotivated by several conjectures due to Nikoghosyan, in a recent article due to Li et al., the aim was to characterize all possible graphs H such that every 1-tough H-free graph is hamiltonian. The almost complete answer was given there by the conclusion that every proper induced subgraph H of $$K_1\cup P_4$$ K 1 ∪ P 4 can act as a forbidden subgraph to ensure that every 1-tough H-free graph is hamiltonian, and that there is no other forbidden subgraph with this property, except possibly for the graph $$K_1\cup P_4$$ K 1 ∪ P 4 itself. The hamiltonicity of 1-tough $$K_1\cup P_4$$ K 1 ∪ P 4 -free graphs, as conjectured by Nikoghosyan, was left there as an open case. In this paper, we consider the stronger property of pancyclicity under the same condition. We find that the results are completely analogous to the hamiltonian case: every graph H such that any 1-tough H-free graph is hamiltonian also ensures that every 1-tough H-free graph is pancyclic, except for a few specific classes of graphs. Moreover, there is no other forbidden subgraph having this property. With respect to the open case for hamiltonicity of 1-tough $$K_1\cup P_4$$ K 1 ∪ P 4 -free graphs we give infinite families of graphs that are not pancyclic.

scholarly journals Forbidden subgraphs of graphs uniquely Hamiltonian-connected from a vertex

1998 ◽  
Vol 187 (1-3) ◽  
pp. 281-290 ◽  
Author(s):  
George R.T. Hendry ◽  
C.J. Knickerbocker ◽  
Patti Frazer Lock ◽  
Michael Sheard
Keyword(s):  
Forbidden Subgraphs ◽  
Hamiltonian Connected

scholarly journals A Quasi-Hole Detection Algorithm for Recognizing k-Distance-Hereditary Graphs, with k < 2

Algorithms ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 105
Author(s):  
Serafino Cicerone
Keyword(s):  
Polynomial Time ◽  
Detection Algorithm ◽  
Recognition Algorithm ◽  
Forbidden Subgraphs ◽  
Induced Subgraph ◽  
Hole Detection

Cicerone and Di Stefano defined and studied the class of k-distance-hereditary graphs, i.e., graphs where the distance in each connected induced subgraph is at most k times the distance in the whole graph. The defined graphs represent a generalization of the well known distance-hereditary graphs, which actually correspond to 1-distance-hereditary graphs. In this paper we make a step forward in the study of these new graphs by providing characterizations for the class of all the k-distance-hereditary graphs such that k<2. The new characterizations are given in terms of both forbidden subgraphs and cycle-chord properties. Such results also lead to devise a polynomial-time recognition algorithm for this kind of graph that, according to the provided characterizations, simply detects the presence of quasi-holes in any given graph.

scholarly journals Three-colourability and forbidden subgraphs. II: polynomial algorithms

2002 ◽  
Vol 251 (1-3) ◽  
pp. 137-153 ◽  
Author(s):  
Bert Randerath ◽  
Ingo Schiermeyer ◽  
Meike Tewes
Keyword(s):  
Polynomial Algorithms ◽  
Forbidden Subgraphs

scholarly journals On planar intersection graphs with forbidden subgraphs

2008 ◽  
Vol 59 (3) ◽  
pp. 205-214 ◽  
Author(s):  
János Pach ◽  
Micha Sharir
Keyword(s):  
Forbidden Subgraphs ◽  
Intersection Graphs

scholarly journals Forbidden subgraphs and the existence of a 2-walk

2014 ◽  
Vol 333 ◽  
pp. 56-61
Author(s):  
Michitaka Furuya
Keyword(s):  
Forbidden Subgraphs

Forbidden Subgraphs Generating Almost the Same Sets

2013 ◽  
Vol 22 (5) ◽  
pp. 733-748 ◽  
Author(s):  
SHINYA FUJITA ◽  
MICHITAKA FURUYA ◽  
KENTA OZEKI
Keyword(s):  
Finite Number ◽  
Symmetric Difference ◽  
Forbidden Subgraphs ◽  
Exceptional Set ◽  
Induced Subgraph ◽  
Connected Graphs ◽  
Graph Property ◽  
The Relationship

Let $\mathcal{H}$ be a set of connected graphs. A graph G is said to be $\mathcal{H}$-free if G does not contain any element of $\mathcal{H}$ as an induced subgraph. Let $\mathcal{F}_{k}(\mathcal{H})$ be the set of k-connected $\mathcal{H}$-free graphs. When we study the relationship between forbidden subgraphs and a certain graph property, we often allow a finite exceptional set of graphs. But if the symmetric difference of $\mathcal{F}_{k}(\mathcal{H}_{1})$ and $\mathcal{F}_{k}(\mathcal{H}_{2})$ is finite and we allow a finite number of exceptions, no graph property can distinguish them. Motivated by this observation, we study when we obtain a finite symmetric difference. In this paper, our main aim is the following. If $|\mathcal{H}|\leq 3$ and the symmetric difference of $\mathcal{F}_{1}(\{H\})$ and $\mathcal{F}_{1}(\mathcal{H})$ is finite, then either $H\in \mathcal{H}$ or $|\mathcal{H}|=3$ and H=C3. Furthermore, we prove that if the symmetric difference of $\mathcal{F}_{k}(\{H_{1}\})$ and $\mathcal{F}_{k}(\{H_{2}\})$ is finite, then H1=H2.

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