Results 51 to 60 of about 735 (221)
Line Graphs and Forbidden Induced Subgraphs
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Lai, Hong-Jian, Šoltés, Ľubomír
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Graphs whose Laplacian eigenvalues are almost all 1 or 2
We explicitly determine all connected graphs whose Laplacian matrices have at most four eigenvalues different from 1 and 2.
Mohammadian Ali, Xu Shanshan
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An Implicit Enumeration Approach for Maximum Ratio Clique Relaxations
ABSTRACT This article proposes an implicit enumeration approach to solve the maximum ratio s$$ s $$‐plex and the maximum ratio s$$ s $$‐defective clique problems. The approach is inspired by the classical Bron‐Kerbosch algorithm for enumerating all maximal cliques in a graph, which is extended to enumerating structures that are hereditary on induced ...
Yehor Blokhin +4 more
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Some Variations of Perfect Graphs
We consider (ψk−γk−1)-perfect graphs, i.e., graphs G for which ψk(H) = γk−1(H) for any induced subgraph H of G, where ψk and γk−1 are the k-path vertex cover number and the distance (k − 1)-domination number, respectively.
Dettlaff Magda +3 more
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Graph Classes Generated by Mycielskians
In this paper we use the classical notion of weak Mycielskian M′(G) of a graph G and the following sequence: M′0(G) = G, M′1(G) = M′(G), and M′n(G) = M′(M′n−1(G)), to show that if G is a complete graph of order p, then the above sequence is a generator ...
Borowiecki Mieczys law +3 more
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Characterising and recognising game-perfect graphs [PDF]
Consider a vertex colouring game played on a simple graph with $k$ permissible colours. Two players, a maker and a breaker, take turns to colour an uncoloured vertex such that adjacent vertices receive different colours.
Dominique Andres, Edwin Lock
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List-3-Coloring ordered graphs with a forbidden induced subgraph [PDF]
Sepehr Hajebi, Yanjia Li, Sophie Spirkl
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Longest cycles in vertex‐transitive and highly connected graphs
Abstract We present progress on three old conjectures about longest paths and cycles in graphs. The first pair of conjectures, due to Lovász from 1969 and Thomassen from 1978, respectively, states that all connected vertex‐transitive graphs contain a Hamiltonian path, and that all sufficiently large such graphs even contain a Hamiltonian cycle.
Carla Groenland +4 more
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Forbidden subgraphs, stability and hamiltonicity
The authors study the stability of some classes of claw-free graphs defined in terms of forbidden subgraphs under the closure operation defined in \textit{Z. Ryjáček} [J. Comb. Theory, Ser. B 70, No.~2, 217-224 (1997; Zbl 0872.05032)]. They characterize all connected graphs \(A\) such that the class of all \(CA\)-free graphs (where \(C\) denotes the ...
Brousek, Jan +2 more
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Tight bounds for intersection‐reverse sequences, edge‐ordered graphs, and applications
Abstract In 2006, Marcus and Tardos proved that if A1,⋯,An$A^1,\dots,A^n$ are cyclic orders on some subsets of a set of n$n$ symbols such that the common elements of any two distinct orders Ai$A^i$ and Aj$A^j$ appear in reversed cyclic order in Ai$A^i$ and Aj$A^j$, then ∑i|Ai|=O(n3/2logn)$\sum _{i} |A^i|=O(n^{3/2}\log n)$.
Barnabás Janzer +3 more
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