4 papers
Fixed Point Constructions in Tilings and Cellular Automata
Ilkka Törmä
The fixed point construction is a method for designing tile sets and cellular automata with highly nontrivial dynamical and computational properties. It produces an infinite hierar…
Complexity of Generic Limit Sets of Cellular Automata
Ilkka Törmä
The generic limit set of a topological dynamical system of the smallest closed subset of the phase space that has a comeager realm of attraction. It intuitively captures the asympt…
Recoding Lie algebraic subshifts
Ville Salo, Ilkka Törmä
We study internal Lie algebras in the category of subshifts on a fixed group -- or Lie algebraic subshifts for short. We show that if the acting group is virtually polycyclic and t…
Cantor-Bendixson ranks of countable SFTs
Ilkka Törmä
We show that the possible Cantor-Bendixson ranks of countable SFTs are exactly the finite ordinals and ordinals of the form , where is a computable ordinal. This result w…