Norm inequalities for sectorial matrices

In this paper, we present some singular values and unitarily invariant norminequalities for sectorial matrices. Let T =(T۱۱ T۱۲T۲۱ T۲۲)۲ M۲n(C) be such that the numericalrange of T is contained in a sectorial region S for some ۲ [۰; ۲ ). It is shown, among otherinequalities, that if f is an increasing function on [۰;۱), then (...)where cT ۲ (۰; ۱] and ∥ : ∥ is an arbitrary unitarily invariant norm.

کلیدواژه ها:

Accretive-dissipative matrix ، Numerical range ، Sectorial matrix ، Unitarily invariant norm.