BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//wp-events-plugin.com//6.4.7.2//EN
TZID:Europe/Paris
X-WR-TIMEZONE:Europe/Paris
BEGIN:VEVENT
UID:0-807@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20220315T110000
DTEND;TZID=Europe/Paris:20220315T120000
DTSTAMP:20220309T083519Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
 s-louise-budzynski-polito/
SUMMARY:Séminaire du LPTMS : Louise Budzynski  (DISAT) - Grand amphi\, bâ
 timent Pascal n° 530 - 15 Mar 22 11:00
DESCRIPTION:The closest vector problem and the spin glass model with extern
 al fields for lossy compression\nLouise Budzynski (Department of Applied S
 cience and Technology of Politecnico di Torino)\nHybrid seminar: onsite + 
 zoom.\n\nZoom link: https://cnrs.zoom.us/j/96894507041?pwd=TVBYWU94UlJ5WUl
 DSENxZkljSFRvdz09\nMeeting ID: 968 9450 7041\nPasscode: PwEm1X\n\nWe consi
 der a high-dimensional random constrained optimization problem in which a 
 set of binary variables is subjected to a linear system of equations. The 
 cost function is a simple linear cost\, measuring the Hamming distance wit
 h respect to a reference configuration. Despite its apparent simplicity\, 
 this problem exhibits a rich phenomenology.\nWe show that different situat
 ions arise depending on the random ensemble of linear systems. When each v
 ariable is involved in at most two linear constraints\, we show that the p
 roblem can be partially solved analytically\, in particular we show that u
 pon convergence\, the zero-temperature limit of the cavity equations retur
 ns the optimal solution.\nWe then study the geometrical properties of more
  general random ensembles. In particular we observe a range in the density
  of constraints at which the systems enters a glassy phase where the cost 
 function has many minima.\nInterestingly\, the algorithmic performances ar
 e only sensitive to a further phase transition affecting the structure of 
 configuration allowed by the linear constraints.\nWe also extend our resul
 ts to variables belonging to GF(q)\, the Galois Field of order q. We show 
 that increasing the value of q allows to achieve a better optimum\, which 
 is confirmed by the Replica Symmetric cavity method predictions. \n
CATEGORIES:seminars
LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors
 ay\, 91405\, France
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay
 \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca
 l n° 530:geo:0,0
END:VEVENT
BEGIN:VTIMEZONE
TZID:Europe/Paris
X-LIC-LOCATION:Europe/Paris
BEGIN:STANDARD
DTSTART:20211031T020000
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
END:STANDARD
END:VTIMEZONE
END:VCALENDAR