Computing (or not) Quasi-periodicity Functions of Tilings

Alexis Ballier (1) , Emmanuel Jeandel (1)

1 LIF - Laboratoire d'informatique Fondamentale de Marseille - UMR 6166

We know that tilesets that can tile the plane always admit a quasi-periodic tiling [4, 8], yet they hold many uncomputable properties [3, 11, 21, 25]. The quasi-periodicity function is one way to measure the regularity of a quasi-periodic tiling. We prove that the tilings by a tileset that admits only quasi-periodic tilings have a recursively (and uniformly) bounded quasi-periodicity function. This corrects an error from [6, theorem 9] which stated the contrary. Instead we construct a tileset for which any quasi-periodic tiling has a quasi-periodicity function that cannot be recursively bounded. We provide such a construction for 1-dimensional effective subshifts and obtain as a corollary the result for tilings of the plane via recent links between these objects [1, 10].

Keywords: tilings; multidimensional symbolic dynamics; quasi-periodicity

Domains: Other [cs.OH]

Alexis Ballier, Emmanuel Jeandel. Computing (or not) Quasi-periodicity Functions of Tilings. Journées Automates Cellulaires 2010, Dec 2010, Turku, Finland. pp.54-64. ⟨hal-00542498⟩