Title: Finiteness for polynomial functors Abstract: If a property of tensors, polynomials, or combinations of these is preserved under linear coordinate changes and characterisable by polynomial equations in the entries of the tensor (or in the coefficients of the polynomial), then it is in fact characterisable by finitely many such equations. The goal of my talk is to give a precise meaning to this statement, to show how it comprises several recent theorems in commutative algebra, and to give an idea about its proof.