$L^p$ Liouville theorems for pluriharmonic functions on gradient Kähler-Ricci solitons

Abstract

We study Liouville-type theorems for real-valued pluriharmonic functions on complete gradient Kähler-Ricci solitons under gradient integrability assumptions. For a complete gradient Kähler-Ricci soliton $(M,g,J,f)$ and a real-valued pluriharmonic function $u$, we investigate conditions under which $u$ must be constant. By introducing a globally defined holomorphic quantity induced by the soliton potential, we obtain new Liouville-type results beyond the range available for harmonic functions. In the steady case, we prove that $u$ is constant whenever $$ \int_M|\nabla u|^p\mathrm{d}v<\infty $$ for some $0<p<\infty$. In the shrinking case, we prove the same conclusion for $0<p\leq 2$. Finally, we construct a complete Kähler example showing that the extension to the range $0<p<1$ relies essentially on the soliton structure and does not hold on general complete Kähler manifolds.