Finding a best approximation pair of points for two polyhedra

Ron Aharoni, Yair Censor, Zilin Jiang

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)509-523
Number of pages15
JournalComputational Optimization and Applications
Issue number2
StatePublished - Nov 1 2018
Externally publishedYes


  • Alternating projections
  • Best approximation pair
  • Cheney–Goldstein theorem
  • Convex polyhedra
  • Half-spaces
  • Halpern–Lions–Wittmann–Bauschke algorithm

ASJC Scopus subject areas

  • Control and Optimization
  • Computational Mathematics
  • Applied Mathematics


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