Decidability vs. undecidability for the word problem in amalgams of inverse semigroups

Wed, 28/01/2015 - 10:15

In 2012 J. Meakin posed the following question: under what conditions is the word problem for amalgamated free products of inverse semigroups decidable?

Some positive results were interrupted by a result of Radaro and Silva showing that the problem is  undecidable even under some nice conditions.  Revisiting the proofs of decidability, we discuss  whether positive results can be achieved for wider classes of inverse semigroups and show how small the distance is between decidability and undecidability.