Abstract
We prove that every triangulation of either of the torus, projective plane and Klein bottle, contains a vertex-spanning planar Laman graph as a subcomplex. Invoking a result of Király, we conclude that every 1-skeleton of a triangulation of a surface of nonnegative Euler characteristic has a rigid realization in the plane using at most 26 locations for the vertices.
Similar content being viewed by others
Notes
This connected sum may have at most two edges contained in no triangle face; however, putting back the triangle which is the intersection of those two discs yields a (nonplanar) pure complex which is strongly-connected and has the same graph, namely same 1-skeleton, hence the graph of this connected sum is 2-rigid.
In case \(x_1=B\) and \(x_k=C\) both \(A'BC\) and \(A''BC\) are 3-cycles, and we chose to name \(A'=A\) rather than \(A''=A\).
In a connected sum of discs along ABC, some of the vertices A, B, C may be singular, but this is irrelevant.
A pinched disc at x is the quotient space of a disc where two distinct points are identified, and x is the resulted singular point. In our case the two identified points are on the boundary of the disc.
References
Adiprasito, K., Nevo, E.: Rigidity with few locations. Israel J. Math. 240(2), 711–723 (2020)
Barnette, D.: Generating the triangulations of the projective plane. J. Combin. Theory Ser. B 33(3), 222–230 (1982)
Barnette, D.W., Edelson, A.: All orientable \(2\)-manifolds have finitely many minimal triangulations. Israel J. Math. 62(1), 90–98 (1988)
Barnette, D.W., Edelson, A.L.: All \(2\)-manifolds have finitely many minimal triangulations. Israel J. Math. 67(1), 123–128 (1989)
Connelly, R.: Rigidity. In: Handbook of Convex Geometry, Vol. A, pp. 223–271. North-Holland, Amsterdam (1993)
Fekete, Zs., Jordán, T.: Rigid realizations of graphs on small grids. Comput. Geom. 32(3), 216–222 (2005)
Fogelsanger, A.L.: The Generic Rigidity of Minimal Cycles. PhD thesis, Cornell University (1988)
Graver, J., Servatius, B., Servatius, H.: Combinatorial Rigidity. Graduate Studies in Mathematics, vol. 2. American Mathematical Society, Providence (1993)
Kalai, G.: Rigidity and the lower bound theorem 1. Invent. Math. 88(1), 125–151 (1987)
Király, Cs.: Rigid realizations of graphs with few locations in the plane. Eur. J. Combin. 94, #103304 (2021)
Lawrencenko, S., Negami, S.: Irreducible triangulations of the Klein bottle. J. Combin. Theory Ser. B 70(2), 265–291 (1997)
Lavrenchenko, S.A.: Irreducible triangulations of the torus. J. Soviet Math. 51(5), 2537–2543 (1990)
Nevo, E., Tarabykin, S.: Vertex spanning planar Laman graphs in triangulated surfaces. Sém. Lothar. Combin. 86B, # 43 (2022)
Sitharam, M., St. John, A., Sidman, J. (eds.): Handbook of Geometric Constraint Systems Principles. Discrete Mathematics and its Applications (Boca Raton). CRC Press, Boca Raton (2019)
Sulanke, Th.: Generating irreducible triangulations of surfaces (2006). arXiv:math/0606687
Sulanke, Th.: Note on the irreducible triangulations of the Klein bottle. J. Combin. Theory Ser. B 96(6), 964–972 (2006)
Whiteley, W.: Vertex splitting in isostatic frameworks. Struct. Topol. 16, 23–30 (1990)
Acknowledgements
An extended abstract to this paper was presented at FPSAC2022 [13]. We thank the anonymous referees of both FPSAC2022 and of DCG for their helpful comments.
Author information
Authors and Affiliations
Corresponding author
Additional information
Editor in Charge: János Pach
Dedicated to the memory of Eli Goodman.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Eran Nevo was partially supported by the Israel Science Foundation grants ISF-1695/15 and ISF-2480/20 and by ISF-BSF joint grant 2016288. Simion Tarabykin was partially supported by ISF grant 1695/15.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Nevo, E., Tarabykin, S. Vertex Spanning Planar Laman Graphs in Triangulated Surfaces. Discrete Comput Geom 72, 912–927 (2024). https://doi.org/10.1007/s00454-023-00517-w
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00454-023-00517-w