Official Mathlib source

MulAction.sum_card_fixedBy_eq_card_orbits_mul_card_group

This declaration comes from Mathlib. Follow the official immutable link below to inspect the exact upstream source; ProofAtlas does not mirror or claim authorship of it.

Exact upstream reference

Package: mathlib
Repository: https://github.com/leanprover-community/mathlib4
Commit: 5e932f97dd25535344f80f9dd8da3aab83df0fe6
Source path: Mathlib/GroupTheory/GroupAction/Quotient.lean:262
SHA-256: sha256:50fc92cfeb4c8df97539ecbe4e6153518bea82afe6da61d531f92a9c0170ebb0
Verified bytes: 22,247

Open source in Mathlib

Why there is no source download here

ProofAtlas links to the official immutable Mathlib source. It does not mirror the Lean file, relicense upstream work, publish a ProofAtlas source archive, or claim a first-party source footprint.