I am interested in examples of infinite-dimensional vector spaces that
- are Banach spaces or even Hilbert spaces
- are measure spaces
Instead of the full vector space, subsets with measure structure are interesting as well.
It is well-known that any non-trivial measure in the infinite-dimensional case cannot be as nice as the finite-dimensional Lebesgue measure. But perhaps there is an interesting measure that is not translation-invariant or defined on a mere subset.
What are examples for such spaces, showing up in research in particular?