Hamiltonian flow over deformations of ordinary double points

We cannot see Mt = {(z1, . . . , zn): n i=1 |zi |2 = 1, z2 1 +···+z2n = t} from M = (z1, . . . , zn): n i=1 |zi |2 = 1, z2 1 +···+z2n = 0 , from the point of view of the Hamiltonian mechanics, even though their CR structures are so different. Nevertheless, in this paper, by using a special kind of the Hamiltonian flow, we write down the Kodaira– Spencer class of this deformation, Mt is an element of primitive forms. © 2007 Elsevier Inc. All rights reserved