Proof of `Formal power series` (2nd statement)
groundedproofs/Lax619925Proofs/Series.lean · lax-619925
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
Reversing a word twice gives the word back, so reversing a series twice is the identity.