Spaces of Spaces

Abstract

Wheeler emphasized the study of Superspace( ) ‐ the space of 3-geometries on a spatial manifold of fixed topology . This is a configuration space for GR; knowledge of configuration spaces is useful as regards dynamics and QM. In this Article I consider furthmore generalized configuration spaces to all levels within the conventional ‘equipped sets’ paradigm of mathematical structure used in fundamental Theoretical Physics. This covers A) the more familiar issue of topology change in the sense of topological manifolds (tied to cobordisms), including via pinched manifolds. B) The less familiar issue of not regarding as fixed the yet deeper levels of structure: topological spaces themselves (and their metric space subcase), collections of subsets and sets. Isham has previously presented quantization schemes for a number of these. In this Article, I consider some classical preliminaries for this program, aside from the most obvious (classical dynamics for each). Rather, I provide I) to all levels Relational and Background Independence criteria, which have Problem of Time facets as consequences. I demonstrate that many of these issues descend all the way down, whilst also documenting at which level the others cease to apply. II) I consider probability theory on configuration spaces. In fact such a stochastic treatment is how to further mathematize the hitherto fairly formal and sketchy subject of records theory (a type of formultion of quantum gravity). Along these lines I provide a number of further examples of records theories. To this example I now add 1) Eech cohomology, 2) Kendall’s random sets, 3) the lattice of topologies on a fixed set. I finally consider 4) sheaves, both as a generalization of Eech cohomology and in connection to the study of stratified manifolds such as Superspace( ) itself.