The dispersionless Lax equations and topological minimal models

It is shown that perturbed rings of the primary chiral fields of the topological minimal models coincide with some particular solutions of the dispersionless Lax equations. The exact formulae for the tree level partition functions ofA_n topological minimal models are found. The Virasoro constraints for the analogue of the -function of the dispersionless Lax equation corresponding to these models are proved.