Frobenius Manifolds and Formality of Lie Algebras of Polyvector Fields

We construct a generalization of the variations of Hodge structures on Calabi-Yau manifolds. It gives a Mirror partner for the theory of genus=0 Gromov-Witten invariantsComment: 12 pages, AMS-TeX; typos and a sign corrected, appendix added. Submitted to IMR