Draft — mutable and not usable as a dependency; its citation marks the draft state.

Proof of `Every streaming string transducer computes a regular function`

groundedproofs/Lax916827Proofs/Results.lean · lax-916827

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.

Read the Lean proof on GitHub

Description

Every streaming string transducer computes a regular function (Theorem C.3.2, from sst to regular): the sst is normalised and simulated by a two-way transducer expanding the final output depth-first (PartC/SSTNorm.leanPartC/SSTNorm.lean, PartC/SSTTwoWay.leanPartC/SSTTwoWay.lean), and two-way transducers compute regular functions (Theorem C.2.9); Transducers.sstiffregularTransducers.sst_iff_regular, left to right.

Attribution

Theorem C.3.2 of Transducers, Part C; formalised by Aristotle (Harmonic).