McCammond's normal forms for free aperiodic semigroups revisited

This paper revisits the solution of the word problem for w-terms interpreted over finite aperiodic semigroups, obtained by J. McCammond. The original proof of correctness of McCammond's algorithm, based on normal forms for such terms, uses McCammond's solution of the word problem for certa...

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Bibliographic Details
Main Author: Almeida, J (author)
Other Authors: Zeitoun, M. (author), Costa, J. C. (author)
Format: article
Language:eng
Published: 2015
Online Access:https://hdl.handle.net/10216/107465
Country:Portugal
Oai:oai:repositorio-aberto.up.pt:10216/107465
Description
Summary:This paper revisits the solution of the word problem for w-terms interpreted over finite aperiodic semigroups, obtained by J. McCammond. The original proof of correctness of McCammond's algorithm, based on normal forms for such terms, uses McCammond's solution of the word problem for certain Burnside semigroups. In this paper, we establish a new, simpler, correctness proof of McCammond's algorithm, based on properties of certain regular languages associated with the normal forms. This method leads to new applications.