... defined in Lemma A.2.4 Boundary Value Problems(iii) G = G(z,ν,x) is continuous strictly increasing in z and, for s ome N>0indepen-dent of ν and x, z−NG(z, ν, x) is decreasing in (0, ... distribution, and reproduction in any medium, provided the original work is properly cited.1. Introduction and main results In the study of the regularity of two-phase elliptic and par abolic ... Hindawi Publishing CorporationBoundary Value ProblemsVolume 20 07, Article ID 570 49, 21 pagesdoi:10.1155/20 07/ 570 49 Research ArticleSubsolutions of Elliptic Operators in Divergence Form and Application...