We investigate the well-known problem of counting graph imbeddings on all oriented surfaces with a focus on graphs that are obtained by pasting together two root-edges of another base graph. We require that the partitioned genus distribution of the base graph with respect to these root-edges be known and that both root-edges have two 2-valent endpoints. We derive general formulas for calculatin...

In a clinical evaluation, thirty-one patients with thoracic esophageal cancer who were treated from 1997 to 2000 were selected as subjects including those who underwent hand sewn anastomosis method, circular stapler method and triangular anastomosis method. Incidence of anastomosis failure was 27.3%, 25.0% and 8.3% for the hand sewn anastomosis method, circular stapler method and triangular ana...

A colouring of a strongly regular graph is an allocation of colours (or treatments) to the vertices of the graph. Such a colouring is balanced if every pair of distinct colours occurs equally often on the ends of an edge. When the graph is the complete regular multipartite graph a balanced colouring is just a balanced incomplete-block design, or 2-design. Some constructions are given. For examp...

Let G and H be connected graphs. The tensor product G + H is a graph with vertex set V(G+H) = V (G)  V(H) and edge set E(G + H) ={(a , b)(x , y)| ax ∈ E(G) & by ∈ E(H)}. The graph H is called the strongly triangular if for every vertex u and v there exists a vertex w adjacent to both of them. In this article the tensor product of G + H under some distancebased topological indices are investiga...

In this paper the chordal graph structures of polynomial sets appearing in triangular decomposition in top-down style are studied when the input polynomial set to decompose has a chordal associated graph. In particular, we prove that the associated graph of one specific triangular set computed in any algorithm for triangular decomposition in top-down style is a subgraph of the chordal graph of ...

Separation of a racemic mixture of ibuprofen at a low concentration level by supercritical fluid chromatography in a simulated moving bed (SFC-SMB) is investigated by simulation. The feasibility of ibuprofen enantiomers separation has been experimentally examined in the literature. Our simulation results show that separation of ibuprofen enantiomers is feasible by this method, and R-ibuprofen a...

A triangular grid graph is a finite induced subgraph of the infinite graph associated with the two-dimensional triangular grid. We show that the problem Hamiltonian Cycle is NP-complete for triangular grid graphs, while a hamiltonian cycle in connected, locally connected triangular grid graph can be found in polynomial time. 2000 Mathematics Subject Classification: 05C38 (05C45, 68Q25).