On Waringʹs problem for many forms and Grassmann defective varieties

This paper is devoted to the classical Waring type problem for several algebraic forms. Its geometric translation in terms of Grassmann defectivity for projective varieties yields the best possible solution whenever the number of polynomials is greater than the number of variables. In particular, together with a classical theorem of Alessandro Terracini, this result gives a complete answer to Waringʹs problem for several ternary forms.