University of Leicester

June 16th 2004

- 11.30 Bennett LT5: Daniel Singh (Sheffield)

"The moduli space of stable n-pointed curves of genus zero" - 12.45 Lunch
- 2.30 Bennett LT5: Peter Jorgensen (Leeds)

``Rings and spaces'' - 3.45 Tea
- 4.30 Bennett LT5: Assaf Libman (Aberdeen)

"On the homotopy type of the uncompleted classifying spaces of p-local finite groups"

ABSTRACT: After introducing the moduli space of stable n pointed curves of genus zero I intend to give a new description for this space and describe a natural isomorphism between them. I will then briefly describe the cohomology of this space if time permits.

Peter Jorgensen (Leeds) "Rings and Spaces"

ABSTRACT: Ring theory and algebraic topology have a convenient meeting point in the form of Differential Graded Algebras (DGAs). On one hand, rings are special DGAs, and the homological machinery built to study DGAs specialises to a slick version of homological ring theory. On the other hand, each topological space gives rise to a singular cochain DGA which encodes information about the space. We shall see how the study of DGAs gives rise to theorems which are simultaneous generalizations of theorems in ring theory and algebraic topology. Assaf Libman (Aberdeen) "On the homotopy type of the uncompleted classifying spaces of p-local finite groups"

ABSTRACT: In this talk I will report on an ongoing project whose aim is to understand the classifying space of a p-local finite group before it is p-completed. This work is joint with Antonio Viruel. Some time ago the normaliser decomposition for p-local finite groups was constructed. Its advantage is in being defined over a poset. We use this construction to show that in some interesting cases the classifying space of a p-local finite group is an Eilenberg-MacLane space. Some interesting consequences in group cohomology are drawn. We can also show that the universal space of this classifying space is finite dimensional if the p-local finite group is not exotic.

TTT45 is partially supported by an LMS Scheme 3 grant. Please let Frank Neumann know if you will be joining us for lunch, as he needs to make specific bookings. Anyone who wishes to participate is welcome: we shall operate the usual arrangements for assistance with travel expenses.

Tea and Coffee will be served in the common room.

For further information email Frank Neumann fn8@mcs.le.ac.uk (or John Greenlees j.greenlees@sheffield.ac.uk or Nige Ray nige@ma.man.ac.uk) if you are interested, so we can make approximately the right amount of tea and coffee.

The meeting is partially supported by a Scheme 3 grant from the London Mathematical Society.

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