  By the integral method we prove that any space-like entire graphic
self-shrinking solution to Lagrangian mean curvature flow in $\R^{2n}_{n}$ with
the indefinite metric $\sum_i dx_idy_i$ is flat. This result improves the
previous ones in \cite{HW} and \cite{CCY} by removing the additional assumption
in their results. In a similar manner, we reprove its Euclidean counterpart
which is established in \cite{CCY}.
