Speaker
Asta Heinesen
(University of Canterbury)
Description
We investigate extremal-foliations and foliation-(in)dependence of averaged space-time quantities, appearing in Buchert's scheme and generalisations hereof. For this purpose we introduce a generalised window-function for spatial hyper surface averaging, and investigate variation of the associated hypersurface-scalar. Surprisingly we find that there are foliation-independent statements to be made about certain physical integrated quantities. However, most integrated/averaged quantities are, not surprisingly, foliation dependent. We discuss methods for bounding the foliation dependence within a class of foliations, and provide physical examples of when such a bound can be useful.
