Mathematics of the USSR-Sbornik · 1971 · 117 citations · 6 references
Natural SciencesGeophysicsDirect RestorationsHeavy Oil RecoverySubsurface Fluid FlowBoundary ConditionsDifferential GeometryOperator TheoryElliptic Boundary-value ProblemsPseudodifferential OperatorsSobolev SpacesSubmanifold Theory
There are investigated elliptic pseudodifferential operators p(x, D) which are degenerate on a submanifold Γ of any codimension. Under certain further assumptions, for the operator which is obtained by adjoining to p(x, D) boundary and coboundary conditions on the submanifold Γ, there are constructed left and right regularizers, and theorems on hypoellipticity and local solvability are proved. In case p(x, D) is defined on a smooth compact manifold it is shown to be noetherian on special weighted spaces of Sobolev type. Bibliography: 24 references.
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Pseudo-differential Operators and Non-elliptic Boundary Problems
Lars Hörmander · Annals of Mathematics · 1966 · 496 citations
ON A CLASS OF HYPOELLIPTIC OPERATORS
V V Grušin · Mathematics of the USSR-Sbornik · 1970 · 184 citations
UNIFORMLY NONELLIPTIC PROBLEMS. I
B. Vaĭnberg, V V Grušin · Mathematics of the USSR-Sbornik · 1967 · 43 citations