Given any sequence τ = (τn)n≥1 of positive real numbers and any set E of complex sequences, we write Eτ for the set of all sequences x = (xn)n≥1 such that x/a = (xn/an)n≥1 ∈ E. We define the sets Wτ = (w∞)τ and W 0 τ = (w0)τ , where w∞ is the set of all sequences such that supn (n −1∑n m=1 |xm|) < ∞, and w0 is the set of all sequences such that limn→∞ (n−1 ∑n m=1 |xm|) = 0. Then we explicitly c...
