Explicit formulas for a family of hypermaps beyond the one-face case

Fuente: arXiv
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Main Authors: Bai, Zi-Wei, Chen, Ricky X. F.
Format: Preprint
Published: 2023
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author Bai, Zi-Wei
Chen, Ricky X. F.
author_facet Bai, Zi-Wei
Chen, Ricky X. F.
contents Enumeration of hypermaps is widely studied in many fields. In particular, enumerating hypermaps with a fixed edge-type according to the number of faces and genus is one topic of great interest. However, it is challenging and explicit results mainly exist for hypermaps having one face, especially for the edge-type corresponding to maps. The first systematic study of one-face hypermaps with any fixed edge-type is the work of Jackson (Trans.~Amer.~Math.~Soc.~299, 785--801, 1987) using group characters. In 2011, Stanley obtained the generating polynomial of one-face hypermaps of any fixed edge-type expressed in terms of the backward shift operator. There are also enormous amount of work on enumerating one-face hypermaps of specific edge-types. The enumeration of hypermaps with more faces is generally much harder. In this paper, we make some progress in that regard, and obtain the generating polynomials and properties for a family of typical two-face hypermaps with almost any fixed edge-type.
format Preprint
id arxiv_https___arxiv_org_abs_2309_11618
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Explicit formulas for a family of hypermaps beyond the one-face case
Bai, Zi-Wei
Chen, Ricky X. F.
Combinatorics
05E10, 05A15, 20B30
Enumeration of hypermaps is widely studied in many fields. In particular, enumerating hypermaps with a fixed edge-type according to the number of faces and genus is one topic of great interest. However, it is challenging and explicit results mainly exist for hypermaps having one face, especially for the edge-type corresponding to maps. The first systematic study of one-face hypermaps with any fixed edge-type is the work of Jackson (Trans.~Amer.~Math.~Soc.~299, 785--801, 1987) using group characters. In 2011, Stanley obtained the generating polynomial of one-face hypermaps of any fixed edge-type expressed in terms of the backward shift operator. There are also enormous amount of work on enumerating one-face hypermaps of specific edge-types. The enumeration of hypermaps with more faces is generally much harder. In this paper, we make some progress in that regard, and obtain the generating polynomials and properties for a family of typical two-face hypermaps with almost any fixed edge-type.
title Explicit formulas for a family of hypermaps beyond the one-face case
topic Combinatorics
05E10, 05A15, 20B30
url https://arxiv.org/abs/2309.11618