Results 51 to 60 of about 778 (78)

On Edge H-Irregularity Strengths of Some Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2021
For a graph G an edge-covering of G is a family of subgraphs H1, H2, . . . , Ht such that each edge of E(G) belongs to at least one of the subgraphs Hi, i = 1, 2, . . . , t. In this case we say that G admits an (H1, H2, . . . , Ht)-(edge) covering.
Naeem Muhammad   +4 more
doaj   +1 more source

The Minimum Size of a Graph with Given Tree Connectivity

open access: yesDiscussiones Mathematicae Graph Theory, 2021
For a graph G = (V, E) and a set S ⊆ V of at least two vertices, an S-tree is a such subgraph T of G that is a tree with S ⊆ V (T). Two S-trees T1 and T2 are said to be internally disjoint if E(T1) ∩ E(T2) = ∅ and V (T1) ∩ V (T2) = S, and edge-disjoint ...
Sun Yuefang, Sheng Bin, Jin Zemin
doaj   +1 more source

Eigenvalues and Perfect Matchings [PDF]

open access: yes
AMS classification: 05C50, 05C70, 05E30.graph;perfect matching;Laplacian matrix;eigenvalues.
Brouwer, A.E., Haemers, W.H.
core   +1 more source

Sharp Upper Bounds on the Clar Number of Fullerene Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2018
The Clar number of a fullerene graph with n vertices is bounded above by ⌊n/6⌋ − 2 and this bound has been improved to ⌊n/6⌋ − 3 when n is congruent to 2 modulo 6.
Gao Yang, Zhang Heping
doaj   +1 more source

On the Independence Number of Traceable 2-Connected Claw-Free Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2019
A well-known theorem by Chvátal-Erdőos [A note on Hamilton circuits, Discrete Math. 2 (1972) 111–135] states that if the independence number of a graph G is at most its connectivity plus one, then G is traceable.
Wang Shipeng, Xiong Liming
doaj   +1 more source

The 2-pebbling property of squares of paths and Graham’s conjecture

open access: yesOpen Mathematics, 2020
A pebbling move on a graph G consists of taking two pebbles off one vertex and placing one pebble on an adjacent vertex. The pebbling number of a connected graph G, denoted by f(G), is the least n such that any distribution of n pebbles on G allows one ...
Li Yueqing, Ye Yongsheng
doaj   +1 more source

Packing Coloring of Some Undirected and Oriented Coronae Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2017
The packing chromatic number χρ(G) of a graph G is the smallest integer k such that its set of vertices V(G) can be partitioned into k disjoint subsets V1, . . . , Vk, in such a way that every two distinct vertices in Vi are at distance greater than i in
Laïche Daouya   +2 more
doaj   +1 more source

Decomposition of Certain Complete Bipartite Graphs into Prisms

open access: yesDiscussiones Mathematicae Graph Theory, 2017
Häggkvist [6] proved that every 3-regular bipartite graph of order 2n with no component isomorphic to the Heawood graph decomposes the complete bipartite graph K6n,6n.
Froncek Dalibor
doaj   +1 more source

Limited packings of closed neighbourhoods in graphs

open access: yes, 2015
The k-limited packing number, $L_k(G)$, of a graph $G$, introduced by Gallant, Gunther, Hartnell, and Rall, is the maximum cardinality of a set $X$ of vertices of $G$ such that every vertex of $G$ has at most $k$ elements of $X$ in its closed ...
Balister, Paul N.   +2 more
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