Mon June 10. Our visitor Kanstantsin Pashkovich gave a talk on how to lower-bound sizes of extended formulations. Given a combinatorial optimization problem (matching, spanning tree, max-cut, traveling salesman problem, ...) one wants to find lower bounds on how many inequalities a Linear Program must have in order to model the problem.The name "extended formulation" comes from the combinatorial optimization practice to start with a Linear Programming formulation, and then try to add a bunch of new variables together with (few) inequalities, so that the original inequalities become redundant. Kostya explained the connection to Communication Complexity. |

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