Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-27T08:06:21.723Z Has data issue: false hasContentIssue false

Generalizations of the Landau–Hadamard inequality and inequalities for quadratic polynomials of operators

Published online by Cambridge University Press:  14 November 2011

Khr. N. Boyadzhiev
Affiliation:
Faculty of Mathematics, University of Sofia, Sofia, Bulgaria

Synopsis

We give generalizations of the Landau–Hadamard inequality ‖u′‖2Ku‖ ‖u″‖ replacing u” by the second-order differential expression u″ − (α + β)u′ + αβu (α, β ∈ ℂ). The new functional inequalities are then used to obtain similar inequalities for dissipative and skew-Hermitian operators.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1986

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1Bennewitz, C.. A general version of the Hardy-Littlewood-Pólya-Everitt (HELP) inequality. Proc. Roy. Soc. Edinburgh Sect. A 97 (1984), 920.Google Scholar
2Bollobás, B. and Partington, J. R.. Inequalities for quadratic polynomials in Hermitian and dissipative operators. Adv. in Math. 51 (1984), 271281.Google Scholar
3Certain, M. W. and Kurtz, T. G.. Landau-Kolmogorov inequalities for semigroups. Proc. Amer. Math. Soc. 63 (1977), 226230.Google Scholar
4Chernoff, P. R.. Optimal Landau-Kolmogorov inequalities for dissipative operators in Hilbert and Banach spaces. Adv. in Math. 34 (1979), 137144.Google Scholar
5Ditzian, Z.. Some remarks on inequalities of Landau and Kolmogorov. Aequationes Math. 12 (1975), 145151.CrossRefGoogle Scholar
6Dunford, N. and Schwartz, J. T.. Linear operators, Part I (New York: Interscience, 1958).Google Scholar
7Epstein, B.. Partial Differential Equations (New York: McGraw-Hill, 1962).Google Scholar
8Evans, W. D. and Everitt, W. N.. A return to the Hardy-Littlewood integral inequality. Proc. Roy. Soc. London Ser. A 380 (1982), 447486.Google Scholar
9Everitt, W. N.. On an extension to an integro-differential inequality of Hardy, Littlewood and Pólya. Proc. Roy. Soc. Edinburgh Sect. A 69 (1971/1972), 295333.Google Scholar
10Hardy, G. H., Littlewood, J. E. and Pólya, G.. Inequalities (Oxford: Clarendon, 1934).Google Scholar
11Kwong, M. K. and Zettl, A.. Ramifications of Landau's inequality. Proc. Roy. Soc. Edinburgh Sect. A 86 (1980), 175212.CrossRefGoogle Scholar
12Pazy, A.. Semigroups of Linear Operators and Applications to Partial Differential Equations (New York: Springer, 1983).CrossRefGoogle Scholar