Equivalence of Linear Tree Transducers with Output in the Free Group

Abstract

We show that equivalence of deterministic linear tree transducers can be decided in polynomial time when their outputs are interpreted over the free group. Due to the cancellation properties offered by the free group, the required constructions are not only more general, but also simpler than the corresponding constructions for proving equivalence of deterministic linear tree-to-word transducers.

Minor changes based on some reviews. A short version of this paper will be published in the proceedings of DLT 2020