Free and projective generalized multinormed spaces

TL;DR

This paper generalizes the concept of p-multinormed spaces to ${f L}$-spaces, describing free and projective spaces using finite dimensional decompositions, and provides a comprehensive characterization for certain 'nice' ${f L}$ spaces.

Contribution

It introduces a new framework for ${f L}$-spaces, generalizing p-multinormed spaces, and characterizes free and projective ${f L}$-spaces through finite dimensional decompositions.

Findings

Description of a functor based on paving ${f L}$ with finite dimensional subspaces

Construction of free ${f L}$-spaces using this functor

Full characterization of projective ${f L}$-spaces for 'nice' ${f L}$

Abstract

The paper investigates free and projective ${\bf L}$-spaces, where ${\bf L}$ is a given normed space. These spaces form a far-reaching generalization of known $p$-multinormed spaces; in particular, if ${\bf L}=L_p(X)$, the ${\bf L}$-spaces can be considered as $p$-multinormed spaces, based on arbitrary $\sigma$-finite measure spaces $X$ (for "canonical" $p$-multinormed spaces, $X=\mathbb N$ with the counting measure). We first describe a "naturally appearing" functor, based on paving ${\bf L}$ with contractively complemented finite dimensional subspaces. This finite dimensionality is essential; it permits us to describe a free ${\bf L}$-space for this functor. As a corollary, we obtain a wide variety of projective ${\bf L}$-spaces. For "nice" ${\bf L}$ (such as the space of simple $p$-integrable functions on a measure space), we obtain a full description of projective ${\bf L}$-spaces.