Some Consequences of the Shadowing Property in Low Dimensions

We consider low-dimensional systems with the shadowing property. In dimension two, we show that the shadowing property for a homeomorphism implies the existence of periodic orbits in every $\epsilon$-transitive class, and in contrast we provide an example of a $C^\infty$ Kupka-Smale diffeomorphism with the shadowing property exhibiting an aperiodic transitive class. Finally we consider the case of transitive endomorphisms of the circle, and we prove that the $\alpha$-H\"older shadowing property with $\alpha>1/2$ implies that the system is conjugate to an expanding map.