Department of

# Mathematics

Seminar Calendar
for events the day of Tuesday, December 6, 2005.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
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1  2  3  4  5                1  2  3    1  2  3  4  5  6  7
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Tuesday, December 6, 2005

11:00 am in 241 Altgeld Hall,Tuesday, December 6, 2005

#### Ring spectra associated to Shimura varieties and the K(n)-local sphere

###### Tyler Lawson (MIT)

Abstract: This talk will be on joint work with Mark Behrens. We will introduce a recent theorem of J. Lurie which generalizes the Goerss-Hopkins-Miller theorem to some even periodic cohomology theories with associated 1-dimensional p-divisible groups rather than merely formal groups. We will discuss some examples studied by Harris and Taylor in their work on the local Langlands correspondence; the ring spectra associated to these could be regarded as higher chromatic analogs of the topological modular forms spectrum TMF. We close with some discussion of how these might be used to give some computational information about the K(n)-local sphere.

1:00 pm in 241 Altgeld Hall,Tuesday, December 6, 2005

#### A method of Andrews and Roy in partition theory

###### Chadwick Gugg (UIUC Math )

Abstract: We discuss Andrews and Roy's vast generalization of an elementary method for proving Ramanujan's congruence modulo 5 for the partition function p(n).

1:00 pm in 241 Altgeld Hall,Tuesday, December 6, 2005

#### A method of Andrews and Roy in partition theory

###### Chadwick Gugg (UIUC Math )

Abstract: We discuss Andrews and Roy's vast generalization of an elementary method for proving Ramanujan's congruence modulo 5 for the partition function p(n)

1:00 pm in 241 Altgeld Hall,Tuesday, December 6, 2005

#### A method of Andrews and Roy in partition theory

###### Chadwick Gugg (UIUC Math )

Abstract: We discuss Andrews and Roy's vast generalization of an elementary method for proving Ramanujan's congruence modulo 5 for the partition function p(n).

2:00 pm in 156 Henry Building,Tuesday, December 6, 2005

#### Analysis area meeting on postdoc hiring

2:00 pm in 345 Altgeld Hall,Tuesday, December 6, 2005

#### A New Hopf Algebra for Computing $tmf$ Homology and the $tmf ###### Mike Hill (MIT) Abstract: A Hopf algebra developed by Andre Henriques and the speaker and used for computing the$tmf$homology of a space or spectrum is presented. This is done using a variant of the Adams spectral sequence in the world of$tmf$-module spectra. This Hope algebra will be used to show that the$tmf$homology of the cofiber of the transfer map$B\Sigma_3->S^0$is a torsion free indecomposable module over$tmf_*\$.

2:00 pm in 243 Altgeld Hall,Tuesday, December 6, 2005

#### Near minimum energy point distributions on surfaces. A simple approach.

###### Prof. Patrick R. Coulton (EIU Department of Mathematics and Computer Science)

Abstract: An important problem in data collection is to find a reasonable distribution of points that are fairly evenly spaced. One approach is to use a potential function (like Coulomb potential). In practice this is often done with Euclidean distances for an embedded surface. I will consider the problem using geodesic distance. Rather than solve the general problem, I will show that by choosing the sample set carefully one can obtain the minimum energy configuration or one that is 'nearly' minimal.

2:00 pm in 241 Altgeld Hall,Tuesday, December 6, 2005

#### A description of sofic groups in terms of nonstandard analysis, III

###### Evgeny Gordon (Eastern Illinois University)

Abstract: Sofic groups were first defined by M. Gromov as a common generalization of amenable groups and residually finite groups. B. Weiss proved that the old problem of Gottschalk on surjunctive groups has a positive solution for sofic groups. The problem of existence of non-sofic groups remains open. In this talk we discuss this topic in terms of nonstandard analysis, which allows us to simplify some definitions and proofs.

3:00 pm in 241 Altgeld Hall,Tuesday, December 6, 2005

#### On the poset of H-linkage properties

###### Qi Liu (UIUC Math)

Abstract: Given a fixed multigraph H with vertices h1,...,hm, a graph G is H-linked if whenever v1,...,vm are vertices in G, there is a subdivision of H in G in which, for all i, vi is the branch vertex representing hi. We prove some results about when being H1-linked implies being H2-linked and when it does not. This is joint work with Douglas B. West and Gexin Yu.

3:00 pm in 243 Altgeld Hall,Tuesday, December 6, 2005

#### The normality of certain lattice varieties

###### William Haboush (UIUC )

Abstract: Lattice varieties are schemes which parametrize families of lattices over the integers in the local Hilbert class field. The subscheme corresponding to lattices contained in a certain lattice will be shown to be normal by constructing a flat cover which is shown to be a complete intersection.