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BEGIN:VEVENT
SUMMARY:The Brauer-Manin obstruction for singular curves and applications 
 for surfaces
DTSTART:20121206T111500
DTEND:20121206T123000
DTSTAMP:20260609T220418Z
UID:e91cc0972313a0c27efe5784971cd0b435e0f43fe71ed3a5e1bed313
CATEGORIES:Conferences - Seminars
DESCRIPTION:Yonathan Harpaz\nThe Brauer-Manin obstruction is conjectured t
 o be essentially the only obstruction for the Hasse principle and weak app
 roximation on smooth curves. In this talk we will show that this claim is 
 false for singular curves. We will construct examples in which the Brauer-
 Manin obstruction is not enough to explain the failure of the Hasse princi
 ple and the etale-Brauer obstruction is not enough to explain the failure 
 of weak approximation. On the positive side\, we show that finite descent 
 is the only obstruction for the Hasse principle in a certain class of sing
 ular curves. Finally\, we will use the examples above to construct project
 ive smooth surfaces for which the étale-Brauer obstruction is not the onl
 y obstruction to the Hasse principle. This is partly a joint work with Ale
 xei Skorobogatov.
LOCATION:AAC006 http://plan.epfl.ch/?zoom=19&recenter_y=5864224.42038&rece
 nter_x=730672.24955&layerNodes=fonds\,batiments\,labels\,events_surface\,e
 vents_line\,events_label\,information\,parkings_publics\,arrets_metro\,eve
 nem
STATUS:CONFIRMED
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