For any genus g \leq 26, and for n \leq 3 in all genus, we prove that every
degree-g polynomial in the psi-classes on Mbar_{g,n} can be expressed as a sum
of tautological classes supported on the boundary with no kappa-classes. Such
equations, which we refer to as topological recursion relations, can be used to
deduce universal equations for the Gromov-Witten invariants of any target.Comment: 17 page