Proof of `A measurable selection principle` (2nd statement)
groundedproofs/Lax606786Proofs/Grassmannian.lean · lax-606786
What this proof establishes
no assumptions
Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.
Description
Open sets of a separable metric space are countable unions of balls.