On Colorings Induced by Low-Index Subgroups of Some Hyperbolic Triangle Group
DOI:
https://doi.org/10.66133/1800wf40Keywords:
coloring, hyperbolic triangle, low-index subgroupAbstract
Tilings have been studied in mathematics since ancient times, traditionally within the framework of Euclidean geometry. In recent years, growing interest has emerged in non-Euclidean tilings, particularly those in spherical and hyperbolic geometry, where regular convex polygons generate highly structured and visually striking patterns. Beyond their theoretical importance, hyperbolic tilings offer meaningful applications in areas such as artistic design, architectural pattern formation, mathematical education, and computer-based visualization, where symmetry and color play a central role. This study investigates colorings induced by low-index subgroups of the hyperbolic triangle group *732. Specifically, it constructs right coset colorings of the group, identifies the structural components of its low-index subgroups, and establishes subgroup properties in relation to their induced colorings. Computational tools were employed using GAP (Groups, Algorithms, and Programming) to generate low-index subgroups of the triangle group *732 and to produce the corresponding right coset colorings of the hyperbolic plane. The results show that tiling the entire hyperbolic plane can be achieved by appropriately joining the vertices of a tiling’s fundamental region to form a single, complete rotation. These findings enhance the understanding of symmetry, subgroup structure, and color organization in hyperbolic geometry. Moreover, the resulting colored tilings provide a mathematical foundation for creating complex visual patterns that may be adapted for architectural surfaces, decorative designs, and interactive educational materials. The study demonstrates how abstract group-theoretic concepts can be translated into visually meaningful representations, thereby bridging pure mathematics with applied and creative disciplines. Future research is recommended to explore induced colorings of low-index subgroups of other hyperbolic triangle groups and related hyperbolic structures.
References
Amidror, I. (2009). The theory of the moiré phenomenon: Volume I: Periodic layers (2nd ed.). Springer.
Aziz, S. (1996). A computer algorithm for coloring a hyperbolic tessellation [Master’s thesis]. University of the Philippines Diliman.
Conway, J., Burgiel, H., & Goodman-Strauss, C. (2008). The symmetries of things. Wellesley.
Coxeter, H. S. M., & Moser, W. O. J. (1980). Generators and relations for discrete groups (4th ed.). Springer.
De Las Peñas, M. L. A. N., Felix, R. P., & Quilingin, M. V. P. (1997). A framework for coloring symmetrical patterns. In Algebras and combinatorics: International Congress (ICAC ’97).
De Las Peñas, M. L. A. N., & Felix, R. P. (1997). Colorings of patterns where the isometries permutating the colors form a subgroup of index at most 3 in the symmetry group of the patterns. Matimyas Matematika, 20(2), 1–13.
Dunham, D. (1986). Artistic fractals. Minnesota Journal of Mathematics, 17(2), 123–130.
Eclarin, L. (2018). Transitive perfect colorings of 2-uniform tilings [Doctoral dissertation]. University of the Philippines Diliman.
Felix, R. P., Cejalvo, F. V., & Quilingin, M. V. P. (2000). Hyperbolic analogues of plane crystallographic groups (NSRI technical report).
Frettlöh, D. (2008). Counting perfect colorings of plane regular tilings. Zeitschrift für Kristallographie.
Grünbaum, B., & Shephard, G. C. (1977). Perfect coloring of the transitive tilings and patterns in the plane. arXiv. https://arxiv.org/pdf/1507.05153
Hernandez, N. H. (2003). On coloring induced by low index subgroups of some hyperbolic triangle groups [Master’s thesis]. University of the Philippines Diliman.
Hernandez, N. H., & Felix, R. P. (2008). Precise colorings of {3,n} tilings of the hyperbolic plane. University of the Philippines Diliman.
Laigo, G. R. (2005). On the construction of perfectly colored semi-regular tilings on the hyperbolic plane [Master’s thesis]. Ateneo de Manila University.
Mackenzie, D. D. (1995). A hyperbolic plane coloring and the simple group of order 168. American Mathematical Monthly, 102(8), 706–715.
Magnus, W., Karrass, A., & Solitar, D. (1976). Combinatorial group theory: Presentations of groups in terms of generators and relations. Dover Publications.
Rigby, J. F. (1997). Perfect precise colourings of triangular tilings, and hyperbolic patchwork. Symmetry: Culture and Science, 5(3–4), 265–299.
Santos, A. (1992). Perfect colorings of a given Archimedean tiling with two orbits of color [Master’s thesis]. University of the Philippines Diliman.
Schattschneider, D. (1978). The plane symmetry groups. American Mathematical Monthly, 85(6), 439–450.
Shubnikov, A. V., & Koptsik, V. A. (1974). Symmetry in science and art (Trans. from Russian). Plenum Press.
The GAP Group. (2008). GAP – Groups, algorithms, and programming (Version 4.4.12) [Computer software]. https://www.gap-system.org
Washburn, D. K., & Crowe, D. W. (1988). Symmetries of culture: Theory and practice of plane pattern analysis. University of Washington Press.
Yao, P. R., & Hernandez, N. S. (2012). 3n precise coloring [Applet]. University of the Philippines Diliman.

