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Proceedings of the American Mathematical Society

Published by the American Mathematical Society since 1950, Proceedings of the American Mathematical Society is devoted to shorter research articles in all areas of pure and applied mathematics.

ISSN 1088-6826 (online) ISSN 0002-9939 (print)

The 2020 MCQ for Proceedings of the American Mathematical Society is 0.85.

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Unitary groups and differential operators
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by Robert M. Kauffman PDF
Proc. Amer. Math. Soc. 30 (1971), 102-106 Request permission

Abstract:

Unitary groups generated by differential operators have special properties that can be used to study completeness of the set of eigenvectors of the infinitesimal generator. Unitary groups also occur in differential operator theory in another manner, associated with unitary equivalence of differential operators. We discuss what happens to ${A_t} = U_t^{ - 1}A{U_t}$ as t approaches infinity provided that ${A_t}$ is a differential operator for all t and A has certain properties.
References
  • Seymour Goldberg, Unbounded linear operators: Theory and applications, McGraw-Hill Book Co., New York-Toronto, Ont.-London, 1966. MR 0200692
  • R. M. Kauffman, Operator theory of a class of ordinary differential expressions, J. Differential Equations (submitted).
  • Peter D. Lax and Ralph S. Phillips, Scattering theory, Pure and Applied Mathematics, Vol. 26, Academic Press, New York-London, 1967. MR 0217440
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Additional Information
  • © Copyright 1971 American Mathematical Society
  • Journal: Proc. Amer. Math. Soc. 30 (1971), 102-106
  • MSC: Primary 47.60
  • DOI: https://doi.org/10.1090/S0002-9939-1971-0282254-X
  • MathSciNet review: 0282254