4 papers
math.AC2005
Perfect Pairs of Ideals and Duals in Numerical Semigroups
Kurt Herzinger, Stephen Wilson, Nándor Sieben +1
This paper considers numerical semigroups that have a non-principal relative ideal such that . We show the existence of an infinite family of…
math.FA1999
A Note on Primitive Equivalence
Nandor Sieben
Primitive equivalence of graphs and matrices was used by Enomoto, Fujii and Watatani to classify Cuntz-Krieger algebras of 3x3 irreducible matrices. In this paper it is shown that…
math.OA1998
C*-actions of r-discrete groupoids and inverse semigroups
John Quigg, Nandor Sieben
Groupoid actions on C*-bundles and inverse semigroup actions on C*-algebras are closely related when the groupoid is r-discrete.
funct-an1997
C*-Crossed Products by Twisted Inverse Semigroup Actions
Nandor Sieben
The notions of Busby-Smith and Green type twisted actions are extended to discrete unital inverse semigroups. The connection between the two types, and the connection with twisted…