5 papers
A note on fixed points of completely positive maps
Gert K. Pedersen
It is shown that a fixed point of a completely positive map on a semi-finite von Neumann algebra must commute with the operators determining the map (the Lueders phenomenon) if the…
Inverse limits of rings and Multiplier rings
Gert K. Pedersen, Francesc Perera
It is proved that the exchange property, the Bass stable rank and the quasi-Bass property are all preserved under surjective inverse limits. This is then applied to multiplier ring…
Jensen's Operator Inequality
Frank Hansen, Gert K. Pedersen
We establish what we consider to be the definitive versions of Jensen's operator inequality and Jensen's trace inequality for functions defined on an interval. This is accomplished…
Extensions and Pullbacks in QB-rings
Pere Ara, Gert K. Pedersen, Francesc Perera
We prove a new extension result for rings that allows us to examine extensions of rings where the ideal is purely infinite and simple. We then use this result to explore vario…
An infinite analogue of rings with stable rank one
Pere Ara, Gert K. Pedersen, Francesc Perera
Replacing invertibility with quasi-invertibility in Bass' first stable range condition we discover a new class of rings, the QB-rings. These constitute a considerable enlargement o…