IJPAM: Volume 52, No. 4 (2009)
Osnabrück, 49069, GERMANY
Abstract.We state the unitary invariants of a pair of projections and and its canonical representation. From this the unitary invariants and canonical form of idempotents are deduced. With this a number of well-known results on projections and idempotents can be derived easily. Finally quadratically normal operators are introduced and analyzed.
Received: March 20, 2009
AMS Subject Classification: 47A46, 47A56
Key Words and Phrases: projections, idempotents
Source: International Journal of Pure and Applied Mathematics