We consider generalizations of the Tutte polynomial on multigraphs obtained by keeping the main recurrence relation T(G)=T(GÂe)+T(G&e) for e # E(G) neither a bridge nor a loop and dropping the relations for bridges and loops. Our first aim is to find the universal invariant satisfying these conditio
Binary contraction of graphs
✍ Scribed by Patrice Assouad
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 410 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0012-365X
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✦ Synopsis
We define the (elementary) binary contraction Gs of a graph G = (V, E) in the following way: if (S) is an induced K,,, not contained into an induced Klv3, then Gs is either the induced subgraph (V\ S), or the graph obtained from (V\S) by adding a new vertex adjacent to those x E V\S such that (S U(x)) has an odd number of edges (according that (S) is contained into an induced K2,* or not). We show that the binary contraction can be performed in some class of graphs such that: the line graphs, the subgraphs of a given root system (and thus the generalized line graphs), the subgraphs of L' (with a given scale and size), the graphs of negative type, . . . .
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