Zulip Chat Archive

Stream: Is there code for X?

Topic: Krein–Smulian Theorem


Christopher Hoskin (Jul 13 2024 at 06:14):

Is there a mathlib proof of the Krein–Smulian theorem:

Let X be a Banach Space with dual X^* and let A be a convex subset of X^* such that A ∩ {x ∈X^* : ‖x‖ ≤ r} is weak star closed for every r > 0, then A is weak star closed?

Thanks.

Yaël Dillies (Jul 13 2024 at 08:38):

Pretty sure we do not

Jireh Loreaux (Jan 22 2026 at 07:53):

I have a proof of this, but I need to clean it up. I'll get around to it sometime in the next several weeks.


Last updated: Feb 28 2026 at 14:05 UTC