نتایج جستجو برای: proximinal

تعداد نتایج: 61  

2016
H. R. Goudarzi

The main purpose of this paper, is to investigate the basic properties of t-proximinal sets. At first we prove some main results and then we see some classified cases, in finite dimensional fuzzy normed spaces.

Journal: :Proceedings of the American Mathematical Society 1976

Journal: :Journal of Approximation Theory 1991

Journal: :Journal of Approximation Theory 1987

Journal: :Int. J. Math. Mathematical Sciences 2004
Darapaneni Narayana T. S. S. R. K. Rao

We consider proximinality and transitivity of proximinality for subspaces of finite codimen-sion in generalized direct sums of Banach spaces. We give several examples of Banach spaces where proximinality is transitive among subspaces of finite codimension. 1. Introduction. Let X be a Banach space and let Y be a closed subspace of X. We recall that Y is said to be a proximinal subspace of X if f...

2013
C. R. Jayanarayanan Tanmoy Paul C. R. JAYANARAYANAN

We derive transitivity of various degrees of proximinality in Banach spaces. When the transitivity does not carry forward to the bigger space we investigate these properties under some additional assumptions of the intermediate space. For instance, we show that if Z ⊆ Y ⊆ X where Z is a finite co-dimensional subspace of X which is strongly proximinal in Y and Y is an M-ideal in X then Z is stro...

Journal: :Journal of Approximation Theory 1999

Journal: :Journal of Approximation Theory 2017
Maciej Ciesielski

Let (E, ‖·‖E) be a symmetric space and let Y ⊂ X be a nonempty subset. For x ∈ X denote PY (x) = {y ∈ Y : ‖x− y‖ = dist(x, Y )}. Any element y ∈ PY (x) is called a best approximant in Y to x. A nonempty set Y ⊂ X is called proximinal or set of existence if PY (x) 6= ∅ for any x ∈ X. A nonempty set Y is said to be a Chebyshev set if it is proximinal and PY (x) is a singleton for any x ∈ E. A sym...

Journal: :Indian Journal of Pure and Applied Mathematics 2021

Lifting properties for Banach spaces are studied. An alternate version of the lifting property due to Lindenstrass and Tzafriri leads a new geometric called quotient pairs (X, J), with J proximinal in X. Several necessary sufficient conditions hold given.

Journal: :Hacettepe Journal of Mathematics and Statistics 2021

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