K\"ahler Ricci solitons and deformation of complex structures

Abstract

Given a compact Fano K\"ahler manifold (M,J) with a K\"ahler Ricci soliton g, we consider smooth families {J_t} of complex deformations of (M,J) which are invariant under the action of a maximal torus T in the full isometry group of (M,g). We prove that, under a certain condition on the spectrum of the Laplacian of g, there exists a smooth family of T-invariant K\"ahler Ricci solitons g_t on every complex manifold (M, J_t) with J_t sufficiently close to J. The result extends a theorem by Koiso on complex deformations of K\"ahler Einstein manifolds.