Best approximation in inner product spaces

@inproceedings{Deutsch2001BestAI,
  title={Best approximation in inner product spaces},
  author={Frank Deutsch},
  year={2001}
}
Inner Product Spaces.- Best Approximation.- Existence and Uniqueness of Best Approximations.- Characterization of Best Approximations.- The Metric Projection.- Bounded Linear Functionals and Best Approximation from Hyperplanes and Half-spaces.- Error of Approximation.- Generalized Solutions of Linear Equations.- The Method of Alternating Projections.- Constrained Interpolation from a Convex Set.- Interpolation and Approximation.- Convexity of Chebyshev Sets. 
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