The category of Silva spaces is not integral

TL;DR

This paper proves that the category of Silva spaces and related categories are not integral, impacting their structural properties and the existence of enough projective or injective objects.

Contribution

It establishes that Silva space categories are not integral and lack enough projective or injective objects, extending to PLS-spaces and related categories.

Findings

Silva space categories are not integral.

These categories lack enough projective or injective objects.

Results hold for variants with weakly compact or nuclear maps.

Abstract

We establish that the category of Silva spaces, aka LS-spaces, formed by countable inductive limits of Banach spaces with compact linking maps as objects and linear and continuous maps as morphisms, is not an integral category. The result carries over to the category of PLS-spaces, i.e., countable projective limits of LS-spaces -- which contains prominent spaces of analysis such as the space of distributions and the space of real analytic functions. As a consequence, we obtain that both categories neither have enough projective nor enough injective objects. All results hold true when 'compact' is replaced by 'weakly compact' or 'nuclear'. This leads to the categories of PLS-, PLS$_{\text{w}}$- and PLN-spaces, which are examples of 'inflation exact categories with admissible cokernels' as recently introduced by Henrard, Kvamme, van Roosmalen and the second-named author.