In this paper we establish the general solution of the functional equationand investigate the Hyers-Ulam-Rassias stability of this equation in quasi-Banach spaces.

In this paper, we obtain the general solution and the generalized Hyers-Ulam-Rassias stability for a cubic functional equationfor a positive integer m ≥ 1.

In this paper we establish the general solution and investigate the Hyers-Ulam-Rassias stability of the following functional equationin the quasi-Banach spaces.

In this paper, we prove the generalized Hyers-Ulam stability for the following quartic functional equation

In this paper we have some new results on sums of Hilbert space frames and Riesz bases. We also have a correction for some results in "S. Obeidat et al., Sums of Hilbert space frames,