Lower bound and upper bound of operators on block weighted sequence spaces |
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Authors: | Rahmatollah Lashkaripour Gholomraza Talebi |
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Institution: | 1. Department of Mathematics, University of Sistan and Baluchestan, Zahedan, Islamic Republic of Iran
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Abstract: | Let $A = {({a_{n,k}})_{n,k \ge 1}}$ be a non-negative matrix. Denote by L v,p,q,F (A) the supremum of those L that satisfy the inequality $$\parallel Ax{\parallel _{v,q,F}} \ge L\parallel x{\parallel _{v,p,F}}$$ where x ? 0 and x ε ? p (v, F) and also v = (v n ) n=1 ∞ is an increasing, non-negative sequence of real numbers. If p = q, we use L v,p,F (A) instead of L v,p,p,F (A). In this paper we obtain a Hardy type formula for L v,p,q,F ( ${H_\mu }$ ), where ${H_\mu }$ is a Hausdorff matrix and 0 < q ? p ? 1. Another purpose of this paper is to establish a lower bound for ‖A W NM ‖ v,p,F , where A W NM is the N?rlund matrix associated with the sequence W = {w n } n=1 t8 and 1 < p < ∞. Our results generalize some works of Bennett, Jameson and present authors. |
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