English

Adjoint entropy vs Topological entropy

General Topology 2011-07-22 v5 Group Theory

Abstract

Recently the adjoint algebraic entropy of endomorphisms of abelian groups was introduced and studied. We generalize the notion of adjoint entropy to continuous endomorphisms of topological abelian groups. Indeed, the adjoint algebraic entropy is defined using the family of all finite-index subgroups, while we take only the subfamily of all open finite-index subgroups to define the topological adjoint entropy. This allows us to compare the (topological) adjoint entropy with the known topological entropy of continuous endomorphisms of compact abelian groups. In particular, the topological adjoint entropy and the topological entropy coincide on continuous endomorphisms of totally disconnected compact abelian groups. Moreover, we prove two Bridge Theorems between the topological adjoint entropy and the algebraic entropy using respectively the Pontryagin duality and the precompact duality.

Keywords

Cite

@article{arxiv.1007.0346,
  title  = {Adjoint entropy vs Topological entropy},
  author = {Anna Giordano Bruno},
  journal= {arXiv preprint arXiv:1007.0346},
  year   = {2011}
}

Comments

18 pages

R2 v1 2026-06-21T15:43:50.755Z