Abstract. We introduce the concept of non-positive operators with respect to a fixed operator defined between two real normed linear spaces. Significantly, we observe that, in certain cases, it is possible to study such type of operators from a geometric point of view. As an immediate application of our study, we explicitly characterize certain classes of non-positive operators between particular pairs of real normed linear spaces. Furthermore, we present a complete characterization of smooth and strictly convex Radon planes in connection with non-positive operators.
DOI: 10.14232/actasm-019-554-z
AMS Subject Classification
(1991): 47L05, 46B20
Keyword(s):
Birkhoff--James orthogonality,
semi-inner-product,
non-positive operator,
polyhedral Banach spaces
received 23.10.2019, revised 5.8.2020, accepted 11.8.2020. (Registered under 54/2019.)
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