Title
Approximating optimization problems over convex functions
Abstract
Many problems of theoretical and practical interest involve finding an optimum over a family of convex functions. For instance, finding the projection on the convex functions in Hk(Ω), and optimizing functionals arising from some problems in economics. In the continuous setting and assuming smoothness, the convexity constraints may be given locally by asking the Hessian matrix to be positive semidefinite, but in making discrete approximations two difficulties arise: the continuous solutions may be not smooth, and functions with positive semidefinite discrete Hessian need not be convex in a discrete sense. Previous work has concentrated on non-local descriptions of convexity, making the number of constraints to grow super-linearly with the number of nodes even in dimension 2, and these descriptions are very difficult to extend to higher dimensions. In this paper we propose a finite difference approximation using positive semidefinite programs and discrete Hessians, and prove convergence under very general conditions, even when the continuous solution is not smooth, working on any dimension, and requiring a linear number of constraints in the number of nodes. Using semidefinite programming codes, we show concrete examples of approximations to problems in two and three dimensions.
Year
DOI
Venue
2008
10.1007/s00211-008-0176-4
Numerische Mathematik
Keywords
Field
DocType
positive semidefinite discrete hessian,discrete sense,convex function,continuous solution,optimization problem,positive semidefinite program,discrete hessians,semidefinite programming code,linear number,positive semidefinite,discrete approximation,numerical analysis,finite difference,three dimensions
Mathematical optimization,Quadratically constrained quadratic program,Mathematical analysis,Convex function,Conic optimization,Convex optimization,Semidefinite embedding,Linear matrix inequality,Semidefinite programming,Convex analysis,Mathematics
Journal
Volume
Issue
ISSN
111
1
0945-3245
Citations 
PageRank 
References 
10
1.01
5
Authors
2
Name
Order
Citations
PageRank
Néstor E. Aguilera18411.53
Pedro Morin233147.99