Journal of Dali University ›› 2023, Vol. 8 ›› Issue (6): 1-8.

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Independent Number and Independent Polynomial of Complete Product of Graph

Yang Limin   

  1. College of Mathematics and Computer Dali University Dali Yunnan 671003 China
  • Received:2022-07-27 Online:2023-06-15 Published:2023-06-26

Abstract:

In graph theory independent number and independent polynomial are NP-hard problems. They are very difficult problems however by transforming the problem an effective method to solve independent number and independent polynomial can be found. By transforming the stable set problem of radix k into a k-order complete subgraph problem the calculation method of independent polynomial is obtained. Anology by transforming the size of the maximum stable set into the size of the maximum complete graph the calculation method of the independent number is obtained. Using combinatorial calculations explicit formulas for the independent number and independent polynomial of many graph's complete product are given. Furthermore using the generating function the Merrifield-Simmons index of the graph is derived. It is proved that some coefficient sequences of independent polynomials are unimodal and some are not and the conjecture that the coefficient sequences of the independent polynomial of trees are unimodal is denied which is of great value and significance to combinatorial mathematics and graph theory.

Key words:

"> stable set">; independent number">; complete product">; independent polynomial">; unimodality

CLC Number: