Reverse triangle inequality in Hilbert $C^{\ast }$-modules

M. Khosravi, H. Mahyar, M. S. Moslehian

We prove several versions of reverse triangle inequality in Hilbert $C^{\ast }$-modules. We show that if $e_1,...,e_m$ are vectors in a Hilbert module $\mathfrak{X}$ over a $C^{\ast }$-alge…