TITLE: Some Lower Bounds on Sparse Outer Approximations of Polytopes

SPEAKER: Andres Iroume

ABSTRACT:

Trying to understand the use of sparse cutting-planes in integer programming solvers, a recent paper by Dey, Molinaro and Wang studied how well polytopes are approximated by using only sparse valid-inequalities. In this talk, we consider "less-idealized" questions such as: effect of sparse inequalities added to linear-programming relaxation, effect on approximation by addition of a budgeted number of dense valid-inequalities, sparse-approximation of polytope under every rotation and approximation by sparse inequalities in specific directions.