Topological dynamics: structural and algebraic aspects, 4 June 2026, Jena

Speakers

• Johannes Kellendonk

  Title: On the Ellis semigroup
  
  Abstract: A topological dynamical system is given by a group of homeomorphisms of a topological space X.
  The functions from X to X form a semigroup F(X) under composition. The Ellis semigroup E(X) of the dynamical systems is the closure, in the topology of pointwise convergence, of its group of homeomorphisms in F(X).
  E(X) has a lot of structure, an algebraic structure, a topological structure and a dynamical structure...

  

• Chunlin Liu

  Title: Sequence Entropy Tuples, Independence, and Mean Sensitivity for Invariant Measures
  
  Abstract: In this talk, I will discuss recent joint work with Leiye Xu and Shuhao Zhang on local notions of complexity for measure-preserving systems under actions of countably infinite discrete groups. The talk will focus on three related notions: sequence entropy tuples, IT tuples, and
  mean sensitive tuples...

  

• Gabriel Fuhrmann

  Title: Prime periods on the interval
  
  Abstract: Given two continuous self-maps f and g on the interval which have all periodic orbits in common (that is, O(x)={x,f(x),...,f^(p-1)(x)} is a p-periodic orbit of f if and only if it is a p-periodic orbit of g but a priori, f may permute the elements of O(x) in a different fashion than g does), it is natural to ask whether f=g on the closure of the periodic points (which is known to coincide with the closure of the recurrent points!)...