2 papers
math.OA2017
HNN extensions of quasi-lattice ordered groups and their operator algebras
Astrid an Huef, Iain Raeburn, Ilija Tolich
The Baumslag-Solitar group is an example of an HNN extension. Spielberg showed that it has a natural positive cone, and that it is then a quasi-lattice ordered group in the sense o…
math.FA2017
Structure theorems for star-commuting power partial isometries
Astrid an Huef, Iain Raeburn, Ilija Tolich
We give a new formulation and proof of a theorem of Halmos and Wallen on the structure of power partial isometries on Hilbert space. We then use this theorem to give a structure th…