A Putnam area inequality for the spectrum of n-tuples of p-hyponormal operators

B. P. Duggal
1999 Glasgow Mathematical Journal  
We prove an n-tuple analogue of the Putnam area inequality for the spectrum of a single p-hyponormal operator.
doi:10.1017/s0017089599000543 fatcat:sv7pex6vlvd2nlpdw3wvpi4ova