The Crossing Number of Hexagonal Graph H3,n in the Projective Plane

Autor: Wang Jing, Cai Junliang, Lv Shengxiang, Huang Yuanqiu
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Discussiones Mathematicae Graph Theory, Vol 42, Iss 1, Pp 197-218 (2022)
Druh dokumentu: article
ISSN: 2083-5892
54485886
DOI: 10.7151/dmgt.2251
Popis: Thomassen described all (except finitely many) regular tilings of the torus S1 and the Klein bottle N2 into (3,6)-tilings, (4,4)-tilings and (6,3)-tilings. Many researchers made great e orts to investigate the crossing number of the Cartesian product of an m-cycle and an n-cycle, which is a special kind of (4,4)-tilings, either in the plane or in the projective plane. In this paper we study the crossing number of the hexagonal graph H3,n (n ≥ 2), which is a special kind of (3,6)-tilings, in the projective plane, and prove that crN1(H3,n)={0,n=2,n-1,n≥3.cr{N_1}\left( {{H_{3,n}}} \right) = \left\{ {\matrix{{0,} \hfill & {n = 2,} \hfill \cr {n - 1,} \hfill & {n \ge 3.} \hfill \cr } } \right.
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