Interior curvature estimates for hypersurfaces of prescribing scalar curvature in dimension three

We prove a priori interior curvature estimates for hypersurfaces of prescribing scalar curvature equations in R³. The method is motivated by the integral method of Warren and Yuan. The new observation here is that we construct a ``Lagrangian'' graph which is a submanifold of bounded mean curvature if the graph function of a hypersurface satisfies a scalar curvature equation.