“…Most of the known results for the nonconvolution case are based on the hypothesis of double summability of the coefficients (∑ +∞ =0 ∑ =0 | , | < +∞); see [1,4,[13][14][15][16][17][18][19]. Another interesting approach, resembling the study of continuous VIDE (see, e.g., [20,21]), basically requires that the coefficient +1 of (5), assumed to be negative, in some sense "prevails" on the summation of the remaining coefficients . Here we would like to add another piece to the framework regarding the analysis of VDE behaviour, by considering hypotheses based on the sign of the coefficients and of their first and second differences.…”