In this paper, the authors will apply De Giorgi-Nash-Moser iteration to establish boundary H?lder estimates for a class of degenerate elliptic equations in piecewise C^(2)-smooth domains.
In the present paper, the rigidity of hypersurfaces in Euclidean space is revisited.The Darboux equation is highlighted and two new proofs of the rigidity are given via energy method and maximal principle, respectively.
