The notion of entropy appears in many fields and this paper is a survey about entropies in
several branches of Mathematics. We are mainly concerned with the topological and the …

We present a unifying approach to the study of entropies in Mathematics, such as measure
entropy, topological entropy, algebraic entropy, set-theoretic entropy. We take into account …

In this expository paper we describe an unifying approach for many known entropies in
Mathematics. First we recall the notion of semigroup entropy h_S in the category S of …

Let R be a ring, let G be a countable amenable group and let RG be a crossed product. The
goal of this paper is to construct, starting with a suitable length function L on the category of …

Recently the strings and the string number of self-maps were used in the computation of the
algebraic entropy of specific abelian group endomorphisms. We introduce two special kinds …

We introduce the notion of intrinsic semilattice entropy h ̃ in the category ℒ qm of
generalized quasimetric semilattices and contractive homomorphisms. By using appropriate …

In the following text for a discrete finite nonempty set $ K $ and a self-map $\varphi: X\to X $
we investigate interaction between different entropies of generalized shift $\mathop …

La tesis está organizada en doce capítulos, divididos en cinco partes. La Parte I comprende
los primeros tres capítulos. En el Capítulo 1 damos una breve introducción a la teoría de las …

In the following text we show set--theoretical entropy of Euler's totient function and
contravariant set--theoretical entropy of Dedekind psi function are zero. Also contravariant …