Shadowing and expansivity in subspaces

Pre-Expansivity in Cellular Automata

We introduce the property of pre-expansivity for cellular automata (CA): it is the property of being expansive on asymptotic pairs of configurations (i.e. configurations that differ in only finitely many positions). Pre-expansivity therefore lies between expansivity and pre-injectivity, two important notions of CA theory. We show that there exist one-dimensional pre-expansive CAs which are not ...

Hyperinvariant subspaces and quasinilpotent operators

For a bounded linear operator on Hilbert space we define a sequence of the so-called weakly extremal vectors‎. ‎We study the properties of weakly extremal vectors and show that the orthogonality equation is valid for weakly extremal vectors‎. ‎Also we show that any quasinilpotent operator $T$ has an hypernoncyclic vector‎, ‎and so $T$ has a nontrivial hyperinvariant subspace‎.

2D cellular automata: expansivity and decidability issues

In this paper we introduce the notion of quasi-expansivity for 2D CA and we show that it shares many properties with expansivity (that holds only for 1D CA). Similarly, we introduce the notions of quasi-sensitivity and prove that the classical dichotomy theorem holds in this new setting. Moreover, we show a tight relation between closingness and openness for 2D CA. Finally, the undecidability o...

ε-weakly Chebyshev subspaces and quotient spaces

LIMIT AVERAGE SHADOWING AND DOMINATED SPLITTING

In this paper the notion of limit average shadowing property is introduced for diffeomorphisms on a compact smooth manifold M and a class of diffeomorphisms is given which has the limit average shadowing property, but does not have the shadowing property. Moreover, we prove that for a closed f-invariant set Lambda  of a diffeomorphism f, if Lambda is C1-stably limit average shadowing and t...