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Absolute convexity in certain topological linear spaces

Published online by Cambridge University Press:  24 October 2008

I. J. Maddox
Affiliation:
University of Lancaster
J. W. Roles
Affiliation:
University of Lancaster

Extract

For r > 0 a non-empty subset U of a linear space is said to be absolutely r-convex if x, yU and |λ|r + |μ|r ≤ 1 together imply λx + μyU, or, equivalently, xl, …, xnU and

It is clear that if U is absolutely r-convex, then it is absolutely s-convex whenever s < r. A topological linear space is said to be r-convex if every neighbourhood of the origin θ contains an absolutely r-convex neighbourhood of the origin. For the case 0 < r ≤ 1, these concepts were introduced and discussed by Landsberg(2).

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1969

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References

REFERENCES

(1)Kelley, J. L., Namioka, I. et al. Linear topological spaces (Van Nostrand; Princeton, 1963).CrossRefGoogle Scholar
(2)Landsberg, M.Lineare topologische Räume, die nicht lokalconvex sind. Math. Z. 65 (1956), 104–12.CrossRefGoogle Scholar
(3)Maddox, I. J.Spaces of strongly summable sequences. Quart. J. Math. Oxford Ser. 18 (1967), 345–55.CrossRefGoogle Scholar
(4)Maddox, I. J.Paranormed sequence spaces generated by infinite matrices. Proc. Cambridge Philos. Soc. (1968).CrossRefGoogle Scholar
(5)Simons, S.The sequence spaces l(pv) and m(pv). Proc. London Math. Soc. (3), 15 (1965), 422–36.CrossRefGoogle Scholar