19 Mars - 25 Mars


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Mardi 20 Mars
Heure: 12:30 - 13:30
Lieu: Salle B107, bâtiment B, Université de Villetaneuse
Résumé: On the Interplay between Simple Mixed Integer Programs and Lot-Sizing
Description: Laurence A. Wolsey After introducing some of the most basic lot-sizing problems and their properties, we show how the study of tight MIP formulations for the convex hull of solutions of such problems has provided more general results for MIPs and vice versa. In particular we demonstrate the importance of compact extended formulations as well as the role of mixing sets, network dual MIPs and single node flow models.
Heure: 14:00 - 17:00
Lieu: Salle B107, bâtiment B, Université de Villetaneuse
Résumé: On lattice polytopes, convex matroid optimization, and degree sequences of hypergraphs
Description: Antoine Deza We introduce a family of polytopes, called primitive zonotopes, which can be seen as a generalization of the permutahedron of type Bd. We discuss connections to the largest diameter of lattice polytopes and to the computational complexity of multicriteria matroidoptimization. Complexity results and open questions are also presented. In particular, we answer a question raised in 1986 by Colbourn, Kocay, and Stinson by showing that deciding whether a given sequence is the degree sequence of a 3-hypergraph is computationallyprohibitive. Based on joint works with Asaf Levin (Technion), George Manoussakis (Paris Sud), Shmuel Onn (Technion).
Vendredi 23 Mars
Heure: 11:00 - 12:30
Lieu: Salle B107, bâtiment B, Université de Villetaneuse
Résumé: Gdt Complexité suite
Description: Paulin de Naurois Suite du premier gdt