... coefficients of L are bounded measurable functions, and aαβxaβαx.Let {gαβx} be a series of functions with gαβ gβα, |α| |β| k. If in certain order weput all multiple indexes α with ... Natural Science Foundation of China no.10971148.8 Boundary Value ProblemsWe denote by X2the completion of X under the norm ·2 and by X1the completion of X with the following normv1⎡⎢⎣Ω⎛⎝|α||β|maαβxDαvDβv ... Keldys, “On certain cases of degeneration of equations of elliptic type on the boundry of adomain,” Doklady Akademii Nauk SSSR, vol. 77, pp. 181–183, 1951.2 O. A. Oleinik and E. V. Radkevich,...