Fragile words and Cayley type transducers

Document Type : Ischia Group Theory 2016


1 TUGraz

2 Dipartimento di Matematica, Politecnico di Milano, Milano, Italia


We address the problem of finding examples of non-bireversible transducers defining free groups, we show examples of transducers with sink accessible from every state which generate free groups, and, in general, we link this problem to the non-existence of certain words with interesting combinatorial and geometrical properties that we call fragile words. By using this notion, we exhibit a series of transducers constructed from Cayley graphs of finite groups whose defined semigroups are free, and thus having exponential growth.


Main Subjects

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