on duality of modular g-riesz bases and g-riesz bases in hilbert c*-modules

In this paper, we investigate duality of modular g-riesz bases and g-riesz bases in hilbert c*-modules. first we give some characterization of g-riesz bases in hilbert c*-modules, by using properties of operator theory. next, we characterize the duals of a given g-riesz basis in hilbert c*-module. in addition, we obtain sufficient and necessary condition for a dual of a g-riesz basis to be again a g-riesz basis. we find a situation for a g-riesz basis to have unique dual g-riesz basis. also, we show that every modular g-riesz basis is a g-riesz basis in hilbert c*-module but the opposite implication is not true.