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The Genus of a Random Bipartite Graph

Published online by Cambridge University Press:  29 August 2019

Yifan Jing
Affiliation:
Department of Mathematics, Simon Fraser University, Burnaby, BC, Canada Email: yifanjing17@gmail.commohar@sfu.ca
Bojan Mohar
Affiliation:
Department of Mathematics, Simon Fraser University, Burnaby, BC, Canada Email: yifanjing17@gmail.commohar@sfu.ca

Abstract

Archdeacon and Grable (1995) proved that the genus of the random graph $G\in {\mathcal{G}}_{n,p}$ is almost surely close to $pn^{2}/12$ if $p=p(n)\geqslant 3(\ln n)^{2}n^{-1/2}$. In this paper we prove an analogous result for random bipartite graphs in ${\mathcal{G}}_{n_{1},n_{2},p}$. If $n_{1}\geqslant n_{2}\gg 1$, phase transitions occur for every positive integer $i$ when $p=\unicode[STIX]{x1D6E9}((n_{1}n_{2})^{-i/(2i+1)})$. A different behaviour is exhibited when one of the bipartite parts has constant size, i.e., $n_{1}\gg 1$ and $n_{2}$ is a constant. In that case, phase transitions occur when $p=\unicode[STIX]{x1D6E9}(n_{1}^{-1/2})$ and when $p=\unicode[STIX]{x1D6E9}(n_{1}^{-1/3})$.

Type
Article
Copyright
© Canadian Mathematical Society 2019

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Footnotes

B.M. was supported in part by the NSERC Discovery Grant R611450 (Canada), by the Canada Research Chairs program, and by the Research Project J1-8130 of ARRS (Slovenia). On leave from IMFM & FMF, Department of Mathematics, University of Ljubljana.

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