Well Posed Optimization Problems and Nonconvex Chebyshev Sets in Hilbert Spaces
Francesca Faraci, Antonio Iannizzotto · SIAM Journal on Optimization · 2008
A result on the existence and uniqueness of metric projection for certain sets is proved, by means of a saddle point theorem. A conjecture, based on such a result and aiming for the construction of a nonconvex Chebyshev set in a Hilbert space, is presented.