Abstract (EN):
The complex algebra of an inverse semigroup with finitely many idempotents in each D -class is stably finite by a result of Munn. This can be proved fairly easily using C* -algebras for inverse semigroups satisfying this condition that have a Hausdorff universal groupoid, or more generally for direct limits of inverse semigroups satisfying this condition and having Hausdorff universal groupoids. It is not difficult to see that a finitely presented inverse semigroup with a non-Hausdorff universal groupoid cannot be a direct limit of inverse semigroups with Hausdorff universal groupoids. We construct here countably many nonisomorphic finitely presented inverse semigroups with finitely many idempotents in each D -class and non-Hausdorff universal groupoids. At this time, there is not a clear C* -algebraic technique to prove these inverse semigroups have stably finite complex algebras.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
15