Complexity as a homeomorphism invariant for tiling spaces

Antoine Julien

Published 2012-12-06, updated 2014-01-08Version 2

It is proved that whenever two aperiodic repetitive tilings with finite local complexity have homeomorphic tiling spaces, their associated complexity functions are asymptotically equivalent in a certain sense (which implies, if the complexity is polynomial, that the exponent of the leading term is preserved by homeomorphism). This theorem can be reworded in terms of $d$-dimensional infinite words: if two $\mathbb{Z}^d$-subshifts (with the same conditions as above) are flow equivalent, their complexity functions are equivalent. An analogue theorem is proved for the repetitivity function, which is a quantitative measure of the recurrence of orbits in the tiling space. How this result relates to the theory of tilings deformations is outlined in the last part.