Proof of `Regular functions are closed under concatenation`
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
Regular functions are closed under concatenation (Lemma C.2.10, second item): map duplicate and the map liftings of the two functions on the two copies (, second conjunct).
Attribution
Lemma C.2.10 of Transducers, Part C; formalised by Aristotle (Harmonic), .