Title of Paper: Spherical classes and the algebraic transfer Author: Nguy\^{e}n H. V. Hung 1991 Mathematics Subject Classification: Primary 55P47, 55Q45, 55S10, 55T15. Address of Author: Department of Mathematics, Vietnam National University, Hanoi, 334 Nguyen Trai Street, Hanoi, Vietnam E-mail address: nhvhung@vnu.edu.vn Abstract: We study a weak form of the classical conjecture which predicts that there are no spherical classes in $Q_0S^0$ except the elements of Hopf invariant one and those of Kervaire invariant one. The weak conjecture is obtained by restricting the Hurewicz homomorphism to the homotopy classes which are detected by the algebraic transfer. We prove that the weak conjecture is equivalent to the following one: Every positive degree Dickson invariant of at least 3 variables belongs to the image of the Steenrod algebra acting on the corresponding polynomial algebra. This conjecture is proved for the case of 3 variables in two different ways.