Dixmier trace

The Dixmier trace is an important concept in the field of functional analysis, particularly in the context of noncommutative geometry and the study of certain types of operators on Hilbert spaces. It is named after Jacques Dixmier, who introduced it. ### Definition The Dixmier trace is a type of trace functional that can be defined for certain unbounded, non-positive operators (often compact or quasi-compact) on a Hilbert space.