We prove several versions of reverse triangle inequality in Hilbert C-modules. We

show that if e1, . . . , em are vectors in a Hilbert module X over a C-algebra A with unit 1 such

that hei, eji = 0 (1 i 6= ...

In this paper, we introduce generalizations of the Bessel inequality in Hilbert spaces

according to the results given by Bombiari, Boas–Bellman and Mitrinovi´c–Peˇcari´c–Fink and

give some extensions of these ...

In this talk, we present a refinement of the Davis--Choi--Jensen

inequality f( Phi(A)) leq Phi(f(A)) for the case where Phi is

a sum of some strictly positive maps.