Small Banach bundles and modules

Abstract

We characterize those (continuously-normed) Banach bundles $\mathcal{E}\to X$ with compact Hausdorff base whose spaces $\Gamma (\mathcal{E})$ of global continuous sections are topologically finitely-generated over the function algebra $C(X)$, answering a question of I. Gogić's and extending analogous work for metrizable $X$. Conditions equivalent to topological finite generation include: (a) the requirement that $\mathcal{E}$ be locally trivial and of finite type along locally closed and relatively $F_{\sigma }$ strata in a finite stratification of $X$; (b) the decomposability of arbitrary elements in ${\ell }^p(\Gamma (\mathcal{E}))$, $1\le p<\infty$ as sums of $\le N$ products in ${\ell }^p(C(X))\cdot \Gamma (\mathcal{E})$ for some fixed $N$; (c) the analogous decomposability requirement for maximal Banach-module tensor products $F{\hat{\otimes }}_{C(X)}\Gamma (\mathcal{E})$ or (d) equivalently, only for $F={\ell }^1(C(X))$.

v2 corrects minor typos; 12 pages + references