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A Tauberian Theorem for Borel-Type Methods of Summability

Published online by Cambridge University Press:  20 November 2018

D. Borwein*
Affiliation:
University of Western Ontario, London, Ontario
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Suppose throughout that α >0, β is real, and Nis a non-negative integer such that αN+ β> 0. A series of complex terms is said to be summable (B, α,β) to l if, as x→ ∞,

where sn= a0 + a1 + … + an.The Borel-type summability method (B, α, β) is regular, i.e., all convergent series are summable (B, α,β) to their natural sums; and (B,1, 1) is the standard Borel exponential method B.

Our aim in this paper is to prove the following Tauberian theorem.

THEOREM. Iƒ

(i) p ≧ – ½, an = o(np), and

(ii) is summable (B, α,β) to l, then the series is summable by the Cesaro method(C, 2p + 1) to l.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1969

References

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3. Hardy, G. H., Divergent series (Oxford, at the Clarendon Press, 1949).Google Scholar
4. Whittaker, E. T. and Watson, G. N., A course of modern analysis, 4th ed. (Cambridge Univ. Press, Cambridge, 1927).Google Scholar