Abstract
We prove that if X is a Banach space and Y is a proximinal subspace of finite codimension in X such that the finite dimensional annihilator of Y is polyhedral, then the metric projection from X onto Y is lower Hausdorff semi continuous. In particular this implies that if X and Y are as above, with the unit sphere of the annihilator space of Y contained in the set of quasi-polyhedral points of X *, then the metric projection onto Y is Hausdorff metric continuous.
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Partially supported under project DST/INT/US-NSF/RPO/141/2003.
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Indumathi, V. Metric Projections and Polyhedral Spaces . Set-Valued Anal 15, 239–250 (2007). https://doi.org/10.1007/s11228-006-0036-2
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DOI: https://doi.org/10.1007/s11228-006-0036-2
Key words
- quasi-polyhedral points
- polyhedral spaces
- proximinal spaces
- metric projection
- lower and upper Hausdorff semi continuity
- Hausdorff metric continuity