Abstract
Given two disjoint convex polyhedra, we look for a best approximation pair relative to them, i.e., a pair of points, one in each polyhedron, attaining the minimum distance between the sets. Cheney and Goldstein showed that alternating projections onto the two sets, starting from an arbitrary point, generate a sequence whose two interlaced subsequences converge to a best approximation pair. We propose a process based on projections onto the half-spaces defining the two polyhedra, which are more negotiable than projections on the polyhedra themselves. A central component in the proposed process is the Halpern–Lions–Wittmann–Bauschke algorithm for approaching the projection of a given point onto a convex set.
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Notes
This acronym was dubbed in [10].
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Acknowledgements
We thank Yehuda Zur for Matlab programming work at the early stages of our research.
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Ron Aharoni: Supported in part by the United States–Israel Binational Science Foundation (BSF) Grant No. 2012031, the Israel Science Foundation (ISF) Grant No. 2023464 and the Discount Bank Chair at the Technion. Yair Censor: Supported in part by BSF Grant No. 2013003. Zilin Jiang: Supported in part by ISF Grant Nos. 1162/15, 936/16.
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Aharoni, R., Censor, Y. & Jiang, Z. Finding a best approximation pair of points for two polyhedra. Comput Optim Appl 71, 509–523 (2018). https://doi.org/10.1007/s10589-018-0021-3
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DOI: https://doi.org/10.1007/s10589-018-0021-3
Keywords
- Best approximation pair
- Convex polyhedra
- Alternating projections
- Half-spaces
- Cheney–Goldstein theorem
- Halpern–Lions–Wittmann–Bauschke algorithm