Oscillation criteria for elliptic systems

Allegretto, W.; Swanson, C. A.

doi:10.1090/S0002-9939-1971-0276592-4

Oscillation criteria for elliptic systems
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by W. Allegretto and C. A. Swanson PDF

Proc. Amer. Math. Soc. 27 (1971), 325-330 Request permission

Abstract:

Oscillation criteria are established for quasilinear elliptic partial differential systems of second order in unbounded domains of Euclidean space. The main departures from earlier investigations are: (1) systems of partial differential equations are considered; (2) the equations are nonlinear; (3) the matrices involved are not required to be positive definite; and (4) a direct method of the Calculus of Variations is used rather than the earlier majorization method.

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