https://hal-ens-lyon.archives-ouvertes.fr/ensl-01651045v2Ramassamy, SanjaySanjayRamassamyUMPA-ENSL - Unité de Mathématiques Pures et Appliquées - ENS Lyon - École normale supérieure - Lyon - CNRS - Centre National de la Recherche ScientifiqueMiquel dynamics for circle patternsHAL CCSD2020[MATH.MATH-DS] Mathematics [math]/Dynamical Systems [math.DS][MATH.MATH-CO] Mathematics [math]/Combinatorics [math.CO][MATH.MATH-MG] Mathematics [math]/Metric Geometry [math.MG]Ramassamy, Sanjay2022-10-27 09:44:272022-11-04 03:44:012022-11-03 09:26:57enJournal articleshttps://hal-ens-lyon.archives-ouvertes.fr/ensl-01651045v2/document10.1093/imrn/rny039https://hal-ens-lyon.archives-ouvertes.fr/ensl-01651045v1application/pdf2We study a new discrete-time dynamical system on circle patterns with the combinatorics of the square grid. This dynamics, called Miquel dynamics, relies on Miquel's six circles theorem. We provide a coordinatization of the appropriate space of circle patterns on which the dynamics acts and use it to derive local recurrence formulas. Isoradial circle patterns arise as periodic points of Miquel dynamics. Furthermore, we prove that certain signed sums of intersection angles are preserved by the dynamics. Finally, when the initial circle pattern is spatially biperiodic with a fundamental domain of size two by two, we show that the appropriately normalized motion of intersection points of circles takes place along an explicit quartic curve.