A Note on Symmetries of WDVV Equations

We investigate symmetries of Witten-Dijkgraaf-E.Verlinde-H.Verlinde (WDVV) equations proposed by Dubrovin from bi-hamiltonian point of view. These symmetries can be viewed as canonical Miura transformations between genus-zero bi-hamiltonian systems of hydrodynamic type. In particular,we show that the moduli space of two-primary models under symmetries of WDVV can be characterized by the polytropic exponent $h$. Furthermore, we also discuss the transformation properties of free energy at genus-one level.