BEGIN:VCALENDAR PRODID:-//eluceo/ical//2.0/EN VERSION:2.0 CALSCALE:GREGORIAN BEGIN:VEVENT UID:9d65fa5a567d08845d991bd508184b36 DTSTAMP:20260608T064325Z SUMMARY:6 from 60 seminar DESCRIPTION:10/06/2026 - Room LIDAM D.251 \;We will host a special Brow nbag Lunch series\, "CORE 6 from 60" where current junior researchers will present 1 paper from each decade of CORE's history.1990s: Wednesday\, 10 June 2026Paul Belleflamme and Jean HindriksYardstick competition and polit ical \;agency problemsIn : Social choice and welfare\, 2005\, vol. 24( 1)\, p. 155-169 \;  \;  \;  \;presented by: Anna Queck URL:https://www.uclouvain.be/en/calendar/core DTSTART;TZID=Europe/Brussels:20260610T125000 DTEND;TZID=Europe/Brussels:20260610T140000 LOCATION:20 Voie du Roman Pays 1348 Louvain-la-Neuve END:VEVENT BEGIN:VEVENT UID:462fee11bf352bd17429717394e4188f DTSTAMP:20260608T064325Z SUMMARY:O.R. Seminar - Benedetto Manca DESCRIPTION:24/06/2026 - Euler building A.002Benedetto Manca \;(Univers ity of Cagliari)will give a presentation onRandom Projections for Mathemat ical ProgrammingAbstract:Random projections are random linear maps which a pproximately preserve geometrical quantities. The Johson-Lindenstrauss Lem ma states that there exist random projections with a relatively small numb er of rows which preserve the pairwise Euclidean distances among a set of points.In the past years several results on the application of random proj ections to Mathematical Programming instances are being obtained\, showing that it is possible to obtain an approximate formulation with less decisi on variables and constraints and therefore easier to solve.In this talk I will introduce the generic framework of random projections for Mathematica l Programming formulations and I will present more in details some results in the case of Linear Programming\, Quadratic Programming and the Minimum Sum of Squares problem.More info about the speaker URL:https://www.uclouvain.be/en/calendar/core DTSTART;TZID=Europe/Brussels:20260624T140000 DTEND;TZID=Europe/Brussels:20260624T150000 LOCATION:Euler Building 1348 Louvain-la-Neuve END:VEVENT BEGIN:VEVENT UID:20fad07f5707703710cddc9e3634daea DTSTAMP:20260608T064325Z SUMMARY:O.R. Seminar - Alexandre Dupont-Bouillard DESCRIPTION:11/06/2026 - 15:00 - CORE C.035 - \;Alexandre Dupont-Bouill ard(Université de Rennes)will give a presentation onPolytopes associated with chordal graphs: induced path\, induced trees and co-3-plexesAbstract: Given a graph G=(V\,E)\, an induced path (resp. tree) is a set of vertices inducing path (resp. tree). We consider the convex hull of 0/1-vector in \\mathbb{R}^V \\times \\mathbb{R}^E encoding induced path (resp. induced t rees).Our first main result is that\, for chordal graphs\, the incidence v ectors of induced paths (respectively\, induced trees) form a \\emph{Hilbe rt basis}: everyinteger vector in their conic hull can be expressed as a n onnegative integer combination of these incidence vectors. Hilbert bases a re of interest in combinatorial optimization due to their close relationsh ip with totally dual integral systems\, which are known to yield integer p olyhedra when theirright-hand side is integral.Somewhat surprisingly\, we do not exploit this connection directly. Instead\, the Hilbert basis prope rty allows us to derive linear descriptions of the\\emph{induced path poly tope} and the \\emph{induced tree polytope} of chordal graphs\, defined as the convex hulls of the corresponding incidence vectors. The description we obtain for the induced tree polytope has polynomial size. For the induc ed path polytope\, our initial system contains exponentially many inequali ties\; we therefore identify those defining facets and show that theirnumb er is\, in fact\, polynomial.These polyhedral characterizations imply that the problems of finding a maximum or minimum-weight induced path or induc ed tree are polynomiallysolvable on chordal graphs.Finally\, we show how t his result can be used to find maximum weight \\emph{co-3-plexes}\, that a re sets of vertices inducing subgraphs of maximum degree 2. In fact\, we e xhibit a polynomial-time algorithm based on column generation solving the latter. \;More info about the speaker URL:https://www.uclouvain.be/en/calendar/core DTSTART;TZID=Europe/Brussels:20260611T150000 DTEND;TZID=Europe/Brussels:20260611T160000 LOCATION:Voie du Roman Pays\, 34 1348 Louvain-la-Neuve END:VEVENT END:VCALENDAR