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Paranormed sequence spaces generated by infinite matrices

Published online by Cambridge University Press:  24 October 2008

I. J. Maddox
Affiliation:
University of Lancaster

Abstract

A paranormed space X = (X, g) is a topological linear space in which the topology is given by paranorm ga real subadditive function on X such that g(θ) = 0, g(x) = g(−x) and such that multiplication is continuous. In the above, θ is the zero in the complex linear space X and continuity of multiplication means that λn → λ, xnx(i.e. g(xnx) → 0) imply λnxn → λx, for scalars λ and vectors x. We shall use the term semimetric function to describe a real subadditive function g on X such that g(θ) = 0, g(x) = g(−x). Two familiar paranormed sequence spaces, which have been extensively studied (3), are l(p) and m(p). For a given sequence p = (gk) of strictly positive numbers, l;(p) is the set of all complex sequences x = (xk) such that and m(p) is the set of x such that sup Throughout, sums and suprema without limits are taken from 1 to ∞. Simons (3) considered only the case in which 0 < pk ≤ 1 so that natural paranorms would seem to be in m(p). In fact Simons showed that g1 was a paranorm for l(p), but that g2 did not satisfy the continuity of multiplication axiom.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1968

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References

REFERENCES

(1)Maddox, I J.On Kuttner's theorem. J. London Math. Soc. (to appear shortly).Google Scholar
(2)Maddox, I. J.Spaces of strongly sun-unable sequences. Quarterly J. Math. (Oxford) (to appear shortly).Google Scholar
(3)Simons, S.The sequence spaces l(pv) and m(pv). Proc. London Math. Soc. (3), 15 (1965), 422–36.CrossRefGoogle Scholar