401 research outputs found
Szeged Fragmental Indices
Novel Szeged indices, defined on unsymmetric matrices, which collect various fragmental topological properties, are proposed. They are illustrated on selected graphs possessing heteroatoms, multiple bonds and stereoisomers. Correlations on organic structures with herbicidal activity and explosive properties support the usefulness of these newly proposed indices
The vertex PI index and Szeged index of bridge graphs
AbstractRecently the vertex Padmakar–Ivan (PIv) index of a graph G was introduced as the sum over all edges e=uv of G of the number of vertices which are not equidistant to the vertices u and v. In this paper the vertex PI index and Szeged index of bridge graphs are determined. Using these formulas, the vertex PI indices and Szeged indices of several graphs are computed
Computing the Szeged and PI Indices of VC5C7[p,q] and HC5C7[p,q] Nanotubes
In this paper we give a GAP program for computing the Szeged and the PI indices of any graph. Also we compute the Szeged and PI indices of VC5C7 [ p,q] and HC5C7 [ p,q] nanotubes by this program
The Fredholm index of locally compact band-dominated operators on
We establish a necessary and sufficient criterion for the Fredholmness of a
general locally compact band-dominated operator on and solve the
long-standing problem of computing its Fredholm index in terms of the limit
operators of . The results are applied to operators of convolution type with
almost periodic symbol
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