Expanding Kähler–Ricci solitons coming out of Kähler cones

Abstract

We give necessary and sufficient conditions for a Kähler equivariant resolution of a Kähler cone, with the resolution satisfying one of a number of auxiliary conditions, to admit a unique asymptotically conical (AC) expanding gradient Kähler-Ricci soliton. In particular, it follows that for any n ∈ N0 and for L a negative line bundle over a compact Kähler manifold D, the total space of the vector bundle L⊕(n+1) admits a unique AC expanding gradient Kähler-Ricci soliton with soliton vector field a positive multiple of the Euler vector field if and only if c1(KD⊗(L)) > 0. This generalises the examples already known in the literature. We further prove a general uniqueness result and show that the space of certain AC expanding gradient Kähler-Ricci solitons on C with positive curvature operator on (1, 1)-forms is path-connected.