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The all-paths transit function of a graph

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

Czechoslovak Mathematical Journal

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.

The Balanced Decomposition Number of TK4 and Series-Parallel Graphs

Shinya Fujita, Henry Liu (2013)

Discussiones Mathematicae Graph Theory

A balanced colouring of a graph G is a colouring of some of the vertices of G with two colours, say red and blue, such that there is the same number of vertices in each colour. The balanced decomposition number f(G) of G is the minimum integer s with the following property: For any balanced colouring of G, there is a partition V (G) = V1 ∪˙ · · · ∪˙ Vr such that, for every i, Vi induces a connected subgraph of order at most s, and contains the same number of red and blue vertices. The function f(G)...

The basis number of some special non-planar graphs

Salar Y. Alsardary, Ali A. Ali (2003)

Czechoslovak Mathematical Journal

The basis number of a graph G was defined by Schmeichel to be the least integer h such that G has an h -fold basis for its cycle space. He proved that for m , n 5 , the basis number b ( K m , n ) of the complete bipartite graph K m , n is equal to 4 except for K 6 , 10 , K 5 , n and K 6 , n with n = 5 , 6 , 7 , 8 . We determine the basis number of some particular non-planar graphs such as K 5 , n and K 6 , n , n = 5 , 6 , 7 , 8 , and r -cages for r = 5 , 6 , 7 , 8 , and the Robertson graph.

The B-Domatic Number of a Graph

Odile Favaron (2013)

Discussiones Mathematicae Graph Theory

Besides the classical chromatic and achromatic numbers of a graph related to minimum or minimal vertex partitions into independent sets, the b-chromatic number was introduced in 1998 thanks to an alternative definition of the minimality of such partitions. When independent sets are replaced by dominating sets, the parameters corresponding to the chromatic and achromatic numbers are the domatic and adomatic numbers d(G) and ad(G). We introduce the b-domatic number bd(G) as the counterpart of the...

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