Abstract: We prove the following assertion: Let T,, j € N , be a sequence in A such that 7" * <fr converges to 0 in A as ;'-»«, for any 4> 6 3! .Then T' • -► 0 in S? as j -* oo.The following problem was presented by A. Kamiñski: Let Tj be a sequence in jA such that F * r/> converges to 0 in ¿A as y -> oo for any <fr e <A.Does F -► 0 in A' as j-»oo?K. Keller gave a positive answer to this question in [3] by using an original method based on a theorem of Grothendieck.But the assertion follows directly from the equality of the linear hull of <A * AA, \in(SAAAAA?), and of S" proved by J. Voigt [9] and even earlier by H. Petzeltová and P. Vrbová [4].Note that lin(^" * 2A) = 3A is known from the following papers: L.