Genus distribution polynomials for bicellular bicolored maps all with real zeros

Fuente: arXiv
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Autores principales: Bai, Zi-Wei, Chen, Ricky X. F.
Formato: Preprint
Publicado: 2024
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author Bai, Zi-Wei
Chen, Ricky X. F.
author_facet Bai, Zi-Wei
Chen, Ricky X. F.
contents Enumerating bicolored maps and maps according to the numbers (and possibly types) of edges, faces, white vertices, black vertices and genus has been an important topic arising in many fields of mathematics and physics. In particular, Jackson (1987), Zagier (1995) and Stanley (2011) respectively obtained some expressions for the generating polynomial of the numbers of one-face bicolored maps with given number of edges and white vertex degree distribution while tracking the number of black vertices. The cases for multiple faces are harder. In this paper, we first obtain the number for that of bicolored maps with two faces, i.e., bicellular, of arbitrary length distribution, and then derive an explicit formula for the corresponding generating polynomial with respect to genus. We next prove that the generating polynomial essentially has only real zeros and thus the genus distribution is log-concave.
format Preprint
id arxiv_https___arxiv_org_abs_2410_07248
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Genus distribution polynomials for bicellular bicolored maps all with real zeros
Bai, Zi-Wei
Chen, Ricky X. F.
Combinatorics
05C31, 05A15, 20B30
Enumerating bicolored maps and maps according to the numbers (and possibly types) of edges, faces, white vertices, black vertices and genus has been an important topic arising in many fields of mathematics and physics. In particular, Jackson (1987), Zagier (1995) and Stanley (2011) respectively obtained some expressions for the generating polynomial of the numbers of one-face bicolored maps with given number of edges and white vertex degree distribution while tracking the number of black vertices. The cases for multiple faces are harder. In this paper, we first obtain the number for that of bicolored maps with two faces, i.e., bicellular, of arbitrary length distribution, and then derive an explicit formula for the corresponding generating polynomial with respect to genus. We next prove that the generating polynomial essentially has only real zeros and thus the genus distribution is log-concave.
title Genus distribution polynomials for bicellular bicolored maps all with real zeros
topic Combinatorics
05C31, 05A15, 20B30
url https://arxiv.org/abs/2410.07248