Institution: | 1.Faculty of Mathematics, “Alexandru Ioan Cuza” University, Bd. Carol I, nr. 11, 700506, Ia?i, Romania ;2.“Octav Mayer” Institute of Mathematics of the Romanian Academy, Ia?i, Romania ;3.Department of Mathematics, “Gheorghe Asachi” Technical University, Bd. Carol I, nr. 11, 700506, Ia?i, Romania ; |