Monday, 22 November 2004, 14:00 (note the unusual weekday!)
Cybernetica Bldg (Akadeemia tee 21), room B101
Abstract: There is an algorithm, devised by Roscoe in Oxford, that allows a ring of databases to circulate updates and ensures that the databases will be consistent when no updates are still circulating. For his proof of the algorithm, Roscoe abstracts an algebraic structure which, quite independently, turns out to be fundamental in knot theory. This talk will explain the algorithm and algebra and show how the connection with knot theory can be seen clearly if the trajectories of the database updates are drawn in space-time.