اصغر رحیمی

Multipliers are operators which have important applications for signal processing and acoustics. In this paper, we investigate invertibility of multipliers and Riesz multipliers in Hilbert C∗-modules. We show, unlike to Riesz multipliers in Hilbert spaces, Riesz multipliers in Hilbert C∗-modules may not be invertible. In addition, by using the modular Riesz bases and uniqueness of dual, we characterize those Riesz bases in Hilbert C∗-modules that their Riesz multipliers are invertible. Also, we obtain some necessary conditions for invertibility of multipliers in Hilbert C∗-modules. Furthermore we show, by using of dual frames, the inverse of any invertible multiplier operator in Hilbert C∗- module is a multiplier operator.