Abstract
Much of the development of lopsided convergence for bifunctions defined on product spaces was in response to motivating applications. A wider class of applications requires an extension that would allow for arbitrary domains, not only product spaces. This leads to an extension of the definition and its implications that include the convergence of solutions and optimal values of a broad class of minsup problems. In the process we relax the definition of lopsided convergence even for the classical situation of product spaces. We now capture applications in optimization under stochastic ambiguity, Generalized Nash games, and many others. We also introduce the lop-distance between bifunctions, which leads to the first quantification of lopsided convergence. This quantification facilitates the study of convergence rates of methods for solving a series of problems including minsup problems, Generalized Nash games, and various equilibrium problems.
Similar content being viewed by others
Notes
We prefer “minsup problem” to “minimax problem” as the inner maximization may not be attained in much of our development.
The need to check subsequences \(N\in \mathcal{N}_\infty ^{\scriptscriptstyle \#}\) is understood, but not explicitly stated in these references.
Statements about convexity/concavity are the only ones that require a linear space in this paper.
We deduce from a counterexample in [10] that the separability assumption cannot be relaxed.
In parametric optimization and elsewhere sup-projections of bifunctions are sometimes called optimal value functions.
A metric space is finitely compact if all its closed balls are compact.
\(D:C\rightrightarrows Y\) is inner semicontinuous if for every \(x^\nu \in C \rightarrow x\in C\), \(\mathop {\mathrm{InnLim}}\nolimits D(x^\nu ) \supset D(x).\)
References
Attouch, H.: Variational Convergence for Functions and Operators, Applicable Mathematics Sciences. Pitman, Totowa (1984)
Attouch, H., Azé, D., Wets, R.J-B: Convergence of convex-concave saddle functions: continuity properties of the Legendre-Fenchel transform with applications to convex programming and mechanics. Ann. l’Inst. H. Poincaré Anal. Nonlinéaire 5, 537–572 (1988)
Attouch, H., Wets, R.J-B: Convergence des points min/sup et de points fixes. C. R. l’Acad. Sci. Paris 296, 657–660 (1983)
Attouch, H., Wets, R.J-B: A convergence theory for saddle functions. Trans. Am. Math. Soc. 280(1), 1–41 (1983)
Attouch, H., Wets, R.J-B: Quantitative stability of variational systems: I. The epigraphical distance. Trans. Am. Math. Soc. 328(2), 695–729 (1991)
Aubin, J.-P.: Mathematical Methods of Game and Economic Theory. North-Holland, Amsterdam (1982)
Aubin, J.-P., Ekeland, I.: Applied Nonlinear Analysis. Issue 1237 of Pure and Applied Mathematics. Wiley, New York (1984)
Aubin, J.-P., Frankowska, H.: Set-Valued Analysis. Birkhäuser, Basel (1990)
Beer, G.: Topologies on Closed and Closed Convex Sets, Volume 268 of Mathematics and Its Applications. Kluwer, Dordrecht (1992)
Beer, G., Rockafellar, R.T., Wets, R.J-B: A characterization of epi-convergence in terms of convergence of level sets. Proc. Am. Math. Soc. 116(3), 753–761 (1992)
Ben-Tal, A., El Ghaoui, L., Nemirovski, A.: Robust Optimization. Princeton University Press, Princeton (2009)
Deride, J., Jofré, A., Wets, R.J-B: Solving deterministic and stochastic equilibrium problems via augmented Walrasian. Comput. Econ. (2018, to appear)
El Ghaoui, L., Calafiore, G.C.: Optimization Models. Cambridge University Press, Cambridge (2014)
Facchinei, F., Kanzow, C.: Generalized Nash equilibrium problems. Ann. Oper. Res. 175(1), 177–221 (2010)
Facchinei, F., Kanzow, C.: Penalty methods for the solution of generalized Nash equilibrium problems. SIAM J. Optim. 20(5), 2228–2253 (2010)
Facchinei, F., Pang, J.-S.: Exact penalty functions for generalized Nash problems. In: Di Pillo, G., Roma, M. (eds.) Large-Scale Nonlinear Optimization, pp. 115–126. Springer, Berlin (2006)
Fukushima, M., Pang, J.-S.: Quasi-variational inequalities, generalized Nash equilibria, and multi-leader-follower games. CMS 2, 21–56 (2005)
Gürkan, G., Pang, J.-S.: Approximations of Nash equilibria. Math. Program. B 117, 223–253 (2009)
Jofré, A., Wets, R.J-B: Continuity properties of Walras equilibrium points. Ann. Oper. Res. 114, 229–243 (2002)
Jofré, A., Wets, R.J-B: Variational convergence of bivariate functions: lopsided convergence. Math. Program. B 116, 275–295 (2009)
Jofré, A., Wets, R.J-B: Variational convergence of bifunctions: motivating applications. SIAM J. Optim. 24(4), 1952–1979 (2014)
Morgan, J., Scalzo, V.: Variational stability of social Nash equilibria. Int. Game Theory Rev. 10(1), 17–24 (2008)
Mosco, U.: Convergence of convex sets and of solutions of variational inequalities. Adv. Math. 3(4), 510–585 (1969)
Nikaido, H., Isoda, K.: Note on noncooperative convex games. Pac. J. Math. 5, 807–815 (1955)
Rockafellar, R.T.: Convex Analysis. Vol. 28 of Princeton Math. Series. Princeton University Press, Princeton (1970)
Rockafellar, R.T., Wets, R.J-B: Variational Analysis, Volume 317 of Grundlehren der Mathematischen Wissenschaft, 3rd printing-2009 edition. Springer, Berlin (1998)
Royset, J.O.: Approximations and solution estimates in optimization. Math. Program. (2018). https://doi.org/10.1007/s10107-017-1165-0
Royset, J.O., Wets, R.J-B: Optimality functions and lopsided convergence. J. Optim. Theory Appl. 169(3), 965–983 (2016)
Royset, J.O., Wets, R.J-B: Variational theory for optimization under stochastic ambiguity. SIAM J. Optim. 27(2), 1118–1149 (2017)
Stein, O.: Bi-level Strategies in Semi-Infinite Programming. Kluwer, Dordrecht (2003)
Sun, H., Xu, H.: Convergence analysis for distributionally robust optimization and equilibrium problems. Math. Oper. Res. 41, 377–401 (2015)
Walkup, D., Wets, R.J-B: Continuity of some convex-cone-valued mappings. Proc. Am. Math. Soc. 18, 229–235 (1967)
Zhang, J., Xu, H., Zhang, L.: Quantitative stability analysis for distributionally robust optimization with moment constraints. SIAM J. Optim. 26(3), 1855–1882 (2016)
Acknowledgements
This material is based upon work supported in part by DARPA under Grant HR0011-14-1-0060 and the U.S. Office of Naval Research under Grant No. N00014-17-2372.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Royset, J.O., Wets, R.JB. Lopsided convergence: an extension and its quantification. Math. Program. 177, 395–423 (2019). https://doi.org/10.1007/s10107-018-1275-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10107-018-1275-3
Keywords
- Lopsided convergence
- Lop-convergence
- Lop-distance
- Attouch–Wets distance
- Epi-convergence
- Hypo-convergence
- Minsup problems
- Generalized Nash games