For a convex function, we consider a space decomposition that allows us to identify a subspace on which a Lagrangian related to the function appears to be smooth. We study a particular trajectory, that we call a fast track, on which a certain second-order expansion of the function can be obtained. We show how to obtain such fast tracks for a general class of convex functions having primal-dual gradient structure. Finally, we show that for a point near a minimizer its corresponding proximal point is on the fast track.

Contact details are reproduced from the original publication and may be historical.

Robert Mifflin

Dept. of Pure and Applied Mathematics, Washington State University, Pullman, WA 99164-3113, U.S.A.

mifflin@math.wsu.edu

Claudia Sagastizábal

National Institute of Pure and Applied Mathematics, Estrada Dona Castorina 110, Jardim Botânico, Rio de Janeiro, RJ 22460-320, Brazil
and: INRIA, BP 105, 78153 Le Chesnay, France

sagastiz@impa.br
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R. Mifflin, C. Sagastizábal. “Proximal Points are on the Fast Track.” Journal of Convex Analysis 9 (2002), No. 2, 563–579. https://doi.org/10.68381/jca09033