Ross building, Hebrew University (Seminar Room 70A)
Abstract: One of the first applications of model categories was Quillen homology. Building on the notion of Beck modules, one defines the cotangent complex of an associative or commutative (dg)-algebras as the derived functor of its abelianization. The latter is a module over the original algebra, and its homology groups are called the (Andre'-)Quillen homology. The caveat of this approach is that the cotangent complex is not defined as a functor on the category of all algebras.
Abstract: In this talk, I will introduce diffeological spaces and some (co)homology theories on these spaces. I will also talk on Thom-Mather spaces and their (co)homology in the diffeological context.
Abstract: The Gromov non-squeezing theorem in symplectic geometry states that is not possible to embed symplectically a ball into a cylinder of smaller radius, although this can be done with a volume preserving embedding. Hence, the biggest radius of a ball that can be symplectically embedded into a symplectic manifold can be used as a way to measure the "symplectic size'' of the manifold. We call the square of this radius times the number \pi the Gromov width of the symplectic manifold. The Gromov width as a symplectic invariant is extended through the notion of "Symplectic Capacity".
Speaker: Imre Leader, Cambridge
Title: Decomposing the Complete r-Graph
The Graham-Pollak theorem states that to decompose the complete graph K_n into complete bipartite subgraphs we need at least n−1 of them. What happens for hypergraphs? In other words, suppose that we wish to decompose the complete r-graph on n vertices into complete r-partite r-graphs; how many do we need?
In this talk we will report on recent progress on this problem.
This is joint work with Luka Milicevic and Ta Sheng Tan.
Topic: Weighted Utilitarianism, Edgeworth, and the Market (joint work with Rossella Argenziano)
Place: Elath Hall, 2nd floor, Feldman Building, Edmond Safra Campus
Time: Sunday, March 6, 2016 at 4:00 p.m.
Refreshments available at 3:30 p.m.
YOU ARE CORDIALLY INVITED
Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus
We consider a Hotelling game where a finite number of retailers choose a location, given that their potential customers are distributed on a network. Retailers do not compete on price but only on location. We show that when the number of retailers is large enough, the game admits a pure Nash equilibrium and we construct it. We then compare the equilibrium cost bore by the consumers with the cost that could be achieved if the retailers followed the dictate of a benevolent planner. We look at this efficiency of equilibrium asymptotically in the number of retailers.