Locally nice embeddings in codimension three
John Bryant, C. L. Seebeck · Bulletin of the American Mathematical Society · 1968
ity and t independence of the operator P(x t D).This permits P to be a quite general operator.Finally, if Pi and P2 reduce to initial value problems, a similar argument is applicable.In this case, conditions on the known function u(x, t) (or v(x f t)) can be imposed on the unknown function v(x, t) (or u(x, t)).With no boundary conditions on u and v, it is no longer necessary to require that {x) satisfy a boundary condition.