Scalar V-soliton equation and K\"ahler-Ricci flow on symplectic quotients

In this paper, we consider the $V$-soliton equation which is a degenerate fully nonlinear equation introduced by La Nave and Tian in their work on K"ahler-Ricci flow on symplectic quotients. One can apply the interpretation to study finite time singularities of the K"ahler-Ricci flow. As in the case of K"ahler-Einstein metrics, we can also reduce the $V$-soliton equation to a scalar equation on K"ahler potentials, which is of Monge-Amp`ere type. We formulate some preliminary estimates for such a scalar equation on a compact K"ahler manifold $M$.