Abstract
Let \(N=2^\alpha 3^\beta\). The normalizer \(\Gamma _B(N)\) of \(\Gamma _0(N)\) in \(PSL(2,\mathbb {R})\) is the triangle group \((2,4,\infty )\) for \(\alpha =1,3,5,7\); \(\beta =0,2\) and the triangle group \((2,6,\infty )\) for \(\alpha =0,2,4,6\); \(\beta =1,3\). In this paper we examine relationship between the normalizer and the regular maps. We define a family of subgroups of the normalizer and then we study maps with quadrilateral and hexagonal faces using these subgroups and calculating the associated arithmetic structure.





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Acknowledgements
The authors would like to thank Prof. Mehmet Akbaş and Prof. David Singerman for their valuable suggestions that improved the earlier versions of the paper. Also, the authors would like to express their sincere gratitude to Prof. Jack Koolen for his support during the review process.
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Yazıcı Gözütok, N., Güler, B.Ö. Quadrilateral and Hexagonal Maps Corresponding to the Subgroups \(\Gamma _0(N)\) of the Modular Group. Graphs and Combinatorics 38, 99 (2022). https://doi.org/10.1007/s00373-022-02503-0
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DOI: https://doi.org/10.1007/s00373-022-02503-0