Clark and Brent on the singularity at T = 0

[Alan Grayson]

I can't recall on which thread I made the argument that if the universe has a finite age, it cannot be infinite in spatial extent. In response, IIRC, Clark and Brent claimed it could've begun as infinite in spatial extent. Isn't there a theorem, which might have been proven by Penrose, that the contracting universe must converge to a point or zero volume containing all matter and energy? What is the name of that theorem, assuming it exists?  TY, AG