Displaying similar documents to “A simple proof of Whitney's Theorem on connectivity in graphs”

The contractible subgraph of 5 -connected graphs

Chengfu Qin, Xiaofeng Guo, Weihua Yang (2013)

Czechoslovak Mathematical Journal

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An edge e of a k -connected graph G is said to be k -removable if G - e is still k -connected. A subgraph H of a k -connected graph is said to be k -contractible if its contraction results still in a k -connected graph. A k -connected graph with neither removable edge nor contractible subgraph is said to be minor minimally k -connected. In this paper, we show that there is a contractible subgraph in a 5 -connected graph which contains a vertex who is not contained in any triangles. Hence, every vertex...

Connected resolvability of graphs

Varaporn Saenpholphat, Ping Zhang (2003)

Czechoslovak Mathematical Journal

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For an ordered set W = { w 1 , w 2 , ⋯ , w k } of vertices and a vertex v in a connected graph G , the representation of v with respect to W is the k -vector r ( v | W ) = ( d ( v , w 1 ) , d ( v , w 2 ) , ⋯ , d ( v , w k ) ) , where d ( x , y ) represents the distance between the vertices x and y . The set W is a resolving set for G if distinct vertices of G have distinct representations with respect to W . A resolving set for G containing a minimum number of vertices is a basis for G . The dimension dim ( G ) is the number of vertices in a basis for G . A resolving set W of G is connected...

The all-paths transit function of a graph

Manoj Changat, Sandi Klavžar, Henry Martyn Mulder (2001)

Czechoslovak Mathematical Journal

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A transit function R on a set V is a function R V × V → 2 V satisfying the axioms u ∈ R ( u , v ) , R ( u , v ) = R ( v , u ) and R ( u , u ) = { u } , for all u , v ∈ V . The all-paths transit function of a connected graph is characterized by transit axioms.

Containers and wide diameters of P 3 ( G )

Daniela Ferrero, Manju K. Menon, A. Vijayakumar (2012)

Mathematica Bohemica

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The P 3 intersection graph of a graph G has for vertices all the induced paths of order 3 in G . Two vertices in P 3 ( G ) are adjacent if the corresponding paths in G are not disjoint. A w -container between two different vertices u and v in a graph G is a set of w internally vertex disjoint paths between u and v . The length of a container is the length of the longest path in it. The w -wide diameter of G is the minimum number l such that there is a w -container of length at most l between any pair...

On integral sum graphs with a saturated vertex

Zhibo Chen (2010)

Czechoslovak Mathematical Journal

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As introduced by F. Harary in 1994, a graph G is said to be an i n t e g r a l s u m g r a p h if its vertices can be given a labeling f with distinct integers so that for any two distinct vertices u and v of G , u v is an edge of G if and only if f ( u ) + f ( v ) = f ( w ) for some vertex w in G . We prove that every integral sum graph with a saturated vertex, except the complete graph K 3 , has edge-chromatic number equal to its maximum degree. (A vertex of a graph G is said to be if it is adjacent to every...