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Cosine Representations of Abelian *-Semigroups and Generalized Cosine Operator Functions

Published online by Cambridge University Press:  20 November 2018

G. D. Faulkner
Affiliation:
North Carolina State University, Raleigh, North Carolina
R. W. Shonkwiler
Affiliation:
Georgia Institute of Technology, Atlanta, Georgia
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In the following R will denote the real numbers, for a Hilbert space H, B(H) and L(H) will denote the collections of bounded linear operators on H and linear, but not necessarily bounded, operators on H respectively. Cosine Operator Functions, namely functions C:RB(H) which satisfy D'Alembert's functional equation

(1)

and

(2)

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1978

References

1. Kurepa, S., A cosine functional equation in Banach algebras, Acta. Sci. Math. 23 (1962), 255267.Google Scholar
2. Kurepa, S., A cosine functional equation in Hilbert space, Can. J. Math. 12 (1960), 45–50.Google Scholar
3. Kurepa, S., A cosine functional equation in n-dimensional vector space, Glasnik mat. fiz. ast. 13 (1958), 169189.Google Scholar
4. Nagy, B., On cosine operator functions in Banach spaces, Acta. Sci. Math. 36 (1974), 281289.Google Scholar
5. Sz.-Nagy, B., Extensions of linear transformations in hilbert space which extend beyond this space New York, (1960).Google Scholar
6. Sova, M., Cosine operator functions, Rozprawy Matematyczne XLIX (Warsaw, 1966).Google Scholar
7. Naimark, M. A., On a representation of additive operator set functions, CR (Doklady) Acad. Sci. USSR, 41 (1943), 359361.Google Scholar