An inclusion theorem for double Cesàro matrices over the space of absolutely -convergent double series

In this work it is shown that if C ( α , β ) and C ( γ , δ ) are double Cesàro matrices with α ≥ γ > − 1 , β ≥ δ > − 1 , then any double series that is ∣ C ( γ , δ ) ∣ k -summable is also ∣ C ( α , β ) ∣ k -summable, k ≥ 1 .