We prove the Liouville theorem
for the mean field equation (also called the conformal curvature equation) in ℝ2, an a
priori bound for solutions of the mean field equation on the negative part of indefinite
nonlinearity, and the symmetry property of mean field equation on an annulus with
zero Dirichlet boundary condition.
Keywords
mean field equation, conformal curvature, indefinite
nonlinearity, moving sphere method, Liouville theorem