UAlberta-PIMS Mathematics and Statistics Colloquium: Jean-Louis Colliot-Thélène

I shall start with reminders on congruences and p-adic numbers, then give Hasse's contribution to the local-global principle. I shall then mention counterexamples to the "Hasse principle" and then describe various ways which have been devised to account for them, and in some cases produce substitutes for this principle.