mathlib

a2e6bf89 - chore(algebraic_topology/cech_nerve): An attempt to speed up the proofs... (#10521)

chore(algebraic_topology/cech_nerve): An attempt to speed up the proofs... (#10521) Let's hope this works! See [zulip discussion](https://leanprover.zulipchat.com/#narrow/stream/144837-PR-reviews/topic/.2310312.20timeouts.20in.20cech_nerve/near/262587999)