摘要

In this paper, we give a new proof of a celebrated theorem of Jorgens which states that every classical convex solution of det del(2)u(x) = 1 in R-2 has to be a second order polynomial. Our arguments do not use complex analysis, and can be applied to establish such Liouville type theorems for solutions of a class of degenerate Monge-Ampere equations. We prove that every convex generalized (or Alexandrov) solution of det del(2)u(x(1), x(2)) = vertical bar x(1)vertical bar(alpha) in R-2, where alpha > -1, has to be u(x(1), x(2)) = alpha/(alpha + 2)(alpha + 1)vertical bar x(1)vertical bar(2+alpha) + ab(2)/2x(1)(2) + bx(1)x(2) + 1/2ax(2)(2) + l(x(1), x(2)) for some constants a>0, b and a linear function l(x(1), x(2)). This work is motivated by the Weyl problem with nonnegative Gauss curvature.