On joint \(\gamma\)-approximate point spectrum of two-norm space operators (Q909949)

Following ideas of \textit{A. Alexiewicz} [ibid. 2, 3-34 (1976; Zbl 0344.46105)], the author defines and studies the joint \(\gamma\)- approximate point spectrum of a k-tuple of pairwise commuting \(\gamma\)- \(\gamma\) linear operators acting on two-norm space. It is shown to have the projection property when restricted to a suitable subalgebra of the algebra of all operators on a given two-norm space.