Approximate Radon-Nikodým representations on Riesz algebras

For the finitely additive case approximate Radon-Nikodym representations are obtained in the setting of Riesz algebras, complementing and generalizing results of Bochner [4], Fefferman [10], de Amo, Chitescu and Díaz Carrillo [1]. Furthermore the possible relations between the various spaces which appear here are given, answering a question of [1]. Various examples show that our results are sharp, there also the class of approximately representable functionals is explicitly characterized, a partial answer to another question of [1]. Finally some open questions are listed.     

Černý’s conjecture and group representation theory

Let us say that a Cayley graph Γ of a group G of order n is a Černy Cayley graph if every synchronizing automaton containing Γ as a subgraph with the same vertex set admits a synchronizing word of length at most (n−1)². In this paper we use the representation theory of groups over the rational numbers to obtain a number of new infinite families of Černy Cayley graphs.     

$${\mathcal{L}_1}$$-spaces with the Radon-Nikodým property containing reflexive subspaces

We show that for every sequence \({(p_n)_{n\in\mathbb{N}}}\) with 1 ≤ p _n  ≤ 2 there exists an \({\mathcal{L}_1}\) -space with the Radon-Nikodým containing an isomorphic copy of \({\ell_1(\ell_{p_n})}\) .