Mehler formulae for matching polynomials of graphs and independence polynomials of clawfree graphs

نویسنده

  • Bodo Lass
چکیده

The independence polynomial of a graph G is the polynomial ∑ I x, summed over all independent subsets I ⊆ V (G). We show that if G is clawfree, then there exists a Mehler formula for its independence polynomial. This was proved for matching polynomials in [18] and extends the combinatorial proof of the Mehler formula imagined by Foata [9]. It implies immediately that all the roots of the independence polynomial of a clawfree graph are real, answering a question posed by Hamidoune [14] and Stanley [27] and solved by Chudnovsky and Seymour [6]. We also prove a Mehler formula for the multivariate matching polynomial, extending results of [18].

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عنوان ژورنال:
  • J. Comb. Theory, Ser. B

دوره 102  شماره 

صفحات  -

تاریخ انتشار 2012