HEBREW UNIVERSITY This thursday: In the Amitsur algebra time slot: (but in room 110) Please notice: Two special talks by Shoham Shamir Thurs April 7th 12:00 room 110 Second talk on Wed April 13th time: TBA Title: Homotopy theory of DG algebras - invariants of the derived category Abstract: (after: Avramov, Thomas, Greenlees, Dwyer and others) The singular cochains functor converts a topological space into a differential graded algebra (DGA). This DGA contains more information about the space than just its cohomology ring. One way to access this additional information is by examining the derived category of the DGA, which is a homotopy invariant of the DGA. Since the cochains DGA is "commutative" its derived category behaves like the derived category of a commutative ring. The obvious strategy is then to choose some notion in commutative algebra, translate it to the derived category of the DGA and see if the resulting structure has topological meaning. This strategy has been highly successful and concepts such as regularity, the prime ideal spectrum, the Gorenstein property, local-cohomology and complete intersection all have interesting topological interpretations. I will describe several of these notions, both the original concept in algebra and its topological meaning. --------------------------------------------------------- Technion Math Net-2 (TECHMATH2) Editor: Michael Cwikel <techm@math.technion.ac.il> Announcement from: Emmanuel Farjoun <farjoun@math.huji.ac.il>