Tension polynomials of graphs
✍ Scribed by Martin Kochol
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 104 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
✦ Synopsis
The tension polynomial F G (k) of a graph G, evaluating the number of nowhere-zero Z k -tensions in G, is the nontrivial divisor of the chromatic polynomial G (k) of G, in that G (k) ¼ k c(G) F G (k), where c(G) denotes the number of components of G. We introduce the integral tension polynomial I G (k), which evaluates the number of nowhere-zero integral tensions in G with absolute values smaller than k. We show that 2 r (G) F G (k) ! I G (k) ! (r (G) þ 1)F G (k), where r (G) ¼ jV(G)j À c(G), and, for every k > 1, F G (k þ 1) ! F G (k) Á k / (k À 1) and I G (k þ 1) ! I G (k) Á k / (k À 1).
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