In this paper, we study cut generating functions for conic sets. Our first main result shows that if the conic set is bounded, then cut generating functions for integer linear programs can easily be adapted to give th...
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In this paper, we study cut generating functions for conic sets. Our first main result shows that if the conic set is bounded, then cut generating functions for integer linear programs can easily be adapted to give the integer hull of the conicinteger program. Then we introduce a new class of cut generating functions which are non decreasing with respect to second-order cone. We show that, under some minor technical conditions, these functions together with integer linear programming-based functions are sufficient to yield the integer hull of intersections of conic sections in R-2. (C) 2016 Elsevier B.V. All rights reserved.
Many classes of mixed integer nonlinear programs (MINLPs) are challenging to solve. A common approach to solve a MINLP is to use a combination of a branch-and-bound algorithm together with convexification and/or cutti...
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Many classes of mixed integer nonlinear programs (MINLPs) are challenging to solve. A common approach to solve a MINLP is to use a combination of a branch-and-bound algorithm together with convexification and/or cutting-planes. In this thesis, we develop new convexification/cutting-plane techniques for two classes of MINLPs: mixed integerconic programs and (non-convex) quadratically constrained quadratic programs. We begin by generalizing a number of important well known results in mixed inte- ger linear programming to the context of mixed integer conic programming. In particu- lar, we introduce a new class of cut generating functions and show that, under some mi- nor technical conditions, these functions, together with integer linear programming-based functions, are sufficient to yield the integer hull of intersections of conic sections in the two-dimensional space. We then focus on the representability of the convex hull of various sets derived from studying substructures of quadratically constrained quadratic programs. One of our main results shows that the convex hull of a single quadratic constraint intersected with a bounded polyhedron is second-order cone representable. For the bipartite bilinear program, a special case of the quadratically constrained quadratic program, we even design and implement an algorithm to obtain this convex hull. In addition, we introduce a new application of the bipartite bilinear program from civil engineering and report very successful computational results for this instance class. Finally, we look at the quadratically constrained quadratic program from a rank-1 per- spective, i. e., casting the non-convexity of the problem using rank-1 constraints. This ap- proach leads us to identify important substructures from which we derive and convexify several classes of sets. We then apply our results to the well-known pooling problem to obtain successful computational results.
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