Weekly Calendar

October 8-12, 2001

Monday Tuesday Wednesday Thursday Friday

Seminars Announcements Conferences Calendar Archive

Items for inclusion in the Weekly Calendar should be submitted via e-mail to Hilda Britt. Deadline for inclusion in the Weekly Calendar is 5 p.m. Thursdays. Speakers are encouraged to provide abstracts.

Orange & Blue Bar

MONDAY, OCTOBER 8

  
RAP ``Etale cohomology'',  159 Altgeld Hall,  10:00 a.m.
  
David Gepner (Graduate Student, UIUC)
Cech cohomology for Grothendieck topologies

  
Math 400 - Introduction to Graduate Mathematics,  245 Altgeld Hall,  4:00 p.m.
  
Professor Matt Ando (Assistant Professor, UIUC)
The Fundamental Group, Orientation and the Stiefel Whitney Class

  
Special Applied Math Seminar,  241 Altgeld Hall,  4:00 p.m.
  
Gary Olsen (Professor of Microbiology, UIUC)
The histories of genes: Issues that limit our understanding of the Tree of Life


TUESDAY, OCTOBER 9

  
Symplectic and Contact Geometry RAP,  143 Henry Bldg,  10:00 a.m.
  
Susan Tolman (Associate Professor, UIUC)
Maslov index for dummies

  
Max Newman Topology,  345 Altgeld Hall,  11:00 a.m.
  
Mark Behrens (University of Chicago)
Root invariants and the Adams spectral sequence
  
Abstract: I will define cosets of the E1 term of a generalized Adams spectral sequence for reasonable ring-spectra E. These ``filtered root invariants" are related to the root invariant. I will present some theorems that govern, under certain ideal circumstances, the passage of these filtered root invariants to the homotopy root invariant in the Adams spectral sequence. The first filtered root invariant is the E-root invariant of Mahowald and Ravenel for general E, and for E the Z/2 Eilenberg-Maclane spectrum, the first non-trivial filtered root invariant is the algebraic root invariant. The existence of higher filtered root invariants will be detected by certain differentials and hidden extensions in the Adams spectral sequence, and the largest non-trivial filtered root invariant ``often" survives to the homotopy root invariant. This behavior is explored for E = bo, HZ/2, BP. I will outline what should be done for E = eo2.

  
RAP ``Spaces of non-positive curvature'',  243 Altgeld Hall,  11:00 a.m.
  
Brad Edge (Graduate Student, UIUC)
Classification of isometries of CAT(0) spaces
  
Abstract: We will present the classification of isometries of CAT(0) spaces as either elliptic, parabolic or hyperbolic. Specific geometric and algebraic properties of hyperbolic isometries will be discussed.

  
Probability and Statistics Seminar,  2 Illini Hall,  11:00 a.m.
See the Joint Seminar Departments of Atmospheric Sciences and Statistics on Wednesday at 3:30 p.m.

  
Several Complex Variables Seminar,  243 Altgeld Hall,  12:00 p.m.
No meeting today

  
Quantum Information Science Seminar,  280 Materials Research Laboratory,  12:00 p.m.
  
Professor Martin Gruebele (UIUC, Dept. of Chemistry)
Dephasing dynamics of highly excited molecules from 6 to 84 degrees of freedom
  
Abstract: With anywhere from 6 to a few 100 degrees of freedom, highly excited organic molecules are an ideal mesoscopic laboratory for studying the dephasing of fairly strongly interacting modes. The 'classic' treatment of vibrational dephasing invokes the Golden Rule and exponential decays, but recent work has shown that the asympotic decays are sub-exponential. This opens up the possibility of coherently controlling mode interactions with lasers. Experiments and quantum dynamics simulations, as well as a new control target functional based on a full quantum Hamiltonian for the molecule-field, will be discussed.

  
Analytic and Elementary Number Theory,  243 Altgeld Hall,  1:00 p.m.
  
Scott Ahlgren (Assistant Professor, UIUC)
A conjecture on the coefficients in a series for p
  
Abstract: We discuss the proof of a conjecture on the behavior of the coefficients of an certain infinite series which represents p.

  
Differential Geometry Seminar,  347 Altgeld Hall,  1:00 p.m.
No meeting this week

  
Logic Seminar,  241 Altgeld Hall,  1:00 p.m.
  
Slawomir Solecki (Associate Professor, UIUC)
Embedding E1 in the coset equivalence relation
  
Abstract: Let G be a Polish group and let H be its analytic subgroup. I will talk about the relationship between the complexity (in the sense of Borel reducibility) of the coset equivalence relation G/H and the existence of a Polish group topology on H preserving the Borel structure of H. In the first talk, I will present the context of the problem and some background material. Later on I plan to present a general theorem on embedding the equivalence relation E1 into G/H including some details of its proof.

  
Geometric Potpourri Seminar,  243 Altgeld Hall,  2:00 p.m.
  
Professor Zoltan Furedi (UIUC Department of Mathematics)
Acute triangles in d-dimensional space
  
Abstract: It is known that a pointset of size exceeding 2d in d-dimensional Euclidean space always contains three points forming an obtuse triangle. The investigation of these point sets leads to the following definition. Call a subset P of d-space (strictly)_diagonal_ if every pair x, y in P lies in (strictly) diagonal position, i.e, one can find parallel hyperplanes Hx, Hy that are tangent to conv(P) at x, y, respectively, and in the strict case Hx, Hy meet conv(P) at precisely x, y, respectively. We review new developments (by I. Talata) and give exponential examples for such sets.

  
Stochastic and Nonlinear Analysis,  347 Altgeld Hall,  2:00 p.m.
  
J. Mattingly (Stanford University)
Ergodic theory of Navier Stokes equation and dissipative PDEs: Infinite dimensional coupling and Gibbs measures
  
Abstract: Given a stochastically forced dissipative PDE such as the 2D Navier Stokes equations, the Ginzburg-Landau equations, or a reaction diffusion equation; is the system Ergodic? This question is fundamental to justifying many assumptions made in modeling. If it is ergodic at what rate does the system equilibrate. I will explain how to address these questions. The analysis will suggest strategies to analysis other properties of these SPDEs. The use of SPDEs in modeling is common in fields ranging from turbulence to interface growth to population dynamics to filtering.

In particular I will show that the stochastically forced 2D Navier Stokes equations converges exponentially to a unique invariant measure. I will discuss under what minimal conditions one should expect ergodic behavior. The central ideas with be illustrated with simple model systems.

Along the way I will discuss some issues which might be of interests to a number of groups.

Probabilists: Coupling in an infinite dimensional Markov chain and in a non-Markovian settings. Exponential mixing, Harris chains, and Lyapunov functions.

Physicists: The description of the system through Gibbs measures and the connections to classical facts from the theory of one dimensional phase transitions. Making use of the enslaving of the high frequencies by the low frequencies.

Analysts: Hypo-ellipticity of degenerate diffusions and why these systems are ``morally elliptic" even though at first glance they seem hypoelliptic. Spectral gaps for diffusions on function spaces.

  
RAP on Geometric Representation Theory,  345 Altgeld Hall,  2:30 p.m.
  
William Haboush, (Professor, UIUC)
Chapter 2 of Chriss and Ginzburg (cont.)

  
Commutative Ring Theory Seminar,  243 Altgeld Hall,  3:00 p.m.
  
Andrew Richardson (Graduate Student, UIUC)
Co-localization via Generalized Matlis Duality

  
Graph Theory and Combinatorics,  241 Altgeld Hall,  3:00 p.m.
  
Abdollah Khodkar (University of Queensland, Australia)
Critical sets in Latin squares
  
Abstract: A Latin square L of order n is an n×n square array in which each cell is occupied by one symbol from a fixed set S of n symbols, so that each symbol occurs exactly once in each row and each column. A critical set in a Latin square is a subset of positions containing just enough information to determine the complete Latin square (similarly, a partly completed crossword puzzle might have a unique completion, even without a list of ``clues" for the words).

It has been conjectured that the smallest possible critical set in a Latin square has size (n2)/4. If so, then it may always be possible to partition a Latin square L into at most four disjoint critical sets in L. We show that Latin squares in a particular class called back-circulant Latin squares can be partitioned into four disjoint critical sets.

  
Study Seminar on Harmonic Analysis,  347 Altgeld Hall,  3:00 p.m.
  
Dr. Jorge Rivera-Noriega (Doob Postdoc, UIUC)
Harmonic analysis in locally flat domains, cont.
  
Abstract: We are studying the paper of C. Kenig and T. Toro on harmonic analysis in locally flat domains

  
RAP - Descriptive set theory and Rosenthal compacta,  241 Altgeld Hall,  4:00 p.m.
  
Maya Bhattacharyya (Graduate Student, UIUC)
Borel sets as clopen sets


WEDNESDAY, OCTOBER 10

  
RAP ``Etale cohomology",  159 Altgeld Hall,  10:00 a.m.
  
David Gepner (Graduate Student, UIUC)
Comparing Cech and etale cohomology

  
Algebraic Geometry RAP,  160 English Bldg,  3:00 p.m.
  
Yong Fu (Graduate Student, UIUC)
Quantum Cohomology
``We will continue with the paper of Fulton and Pandharipande"

  
Joint Seminar Departments of Atmospheric Sciences & Statistics,  106B8 Engineering Hall,  3:30 p.m.
  
Professor Ivan Astin (Environmental System Sciences Center, Reading University)
From ADM to GANDER: Sampling Studies for Proporsed Satellite Instruments with Minimal Swath Width
  
Abstract: A large number of satellite instrument systems are proposed that will make measurements only along (or parallel to) their track over the Earth's surface. Some general spatial and temporal sampling problems associated with such instruments will be presented, as will some specific problems for the ADM and GANDER missions. The ADM (Atmospheric Dynamics Mission) makes use of UV lidar returns from clear-air. However, on average over half of the globe is covered by cloud at any one time. Hence, there is a strong likelihood that its data may be contaminated by cloud. Similarly, an optically-thick cloud may not be penetrated by a lidar pulse, resulting in unovbservable regions that are overshadowed by the cloud. A proposed strategy to overcome this by slecting only uncontaminiated sections along track is investigated using data from a near identical airborne UV lidar operated during the CLARE '98 campaign. The GANDER (Global Altimeter Network Designed to Evaluate Risk) mission attempts to make improvements in ocean wave height measurements by increasing the sampling rates, both spatially and temporally, over current altimeters carried on micro-statellites. The improvement this gives, and an effort to optimize their orbits, is presented from simulations sampling significant wave height data from the ECMWF reanalysis dataset.
Conversation and Cookies at 2:45 p.m. in Room 108 Atmos Sci Bldg

  
RAP - Conformal invariance, intersection exponents and critical percolation,  145 Altgeld Hall,  4:00 p.m.
  
Robert Bauer (Assistant Professor, UIUC)
Intersection exponents for planar Brownian motion, III

  
Information Protection Seminar,  114 CSRL,  4:30 p.m.
  
Diana White (Graduate Student, UIUC)
Identity Based Encryption from the Weil pairing
  
Abstract: Did you know you can use your e-mail address as a public key for cryptography? Did you know that the Weil pairing on elliptic curves makes this possible? An Identity Based Encryption (IBE) scheme is a public-key cryptosystem in which any string can be used as a public key. Shamir requested such a system in 1984 as a method for simplifying certificate management in e-mail systems. Boneh and Franklin recently proposed a fully functional IBE scheme, which forms the basis of this talk.

This talk is designed to be interesting and accessible to mathematicians, engineers, and computer scientists (or anyone with a basic background in mathematics or cryptography). We will define and motivate an IBE scheme, give a brief introduction to elliptic curves, define the Weil Pairing (possibly prove some properties of it) and show how it can be used for the basis of an IBE scheme. We may also explore generalizations (Tate pairing) and other applications (delegation of decryption capabilities).

  
Nonstandard Analysis Seminar,  243 Altgeld Hall,  4:00 p.m.
  
Yevgeniy Gordon (Professor, Eastern Illinois University)
On approximations of locally compact groups by finite quasigroups, II


THURSDAY, OCTOBER 11

  
Math - Physics (BCDE) Lunch Seminar,  6-110 Engineering Science Bldg,  12:05 p.m.
  
Sergei Gukov (Harvard)
Singularities of Spin(7) manifolds in M-theory
  
Abstract: We will discuss M-theory on two classes of manifolds of Spin(7) holonomy that are developing an isolated conical singularity. We construct explicitly a new class of Spin(7) manifolds and analyse in detail the topology of the corresponding classical spacetimes. We discover also an intricate interplay between various anomalies in M-theory, string theory, and gauge theory within these models, and in particular find a connection between half-integral G-fluxes in M-theory and Chern-Simons terms of the N=1, D=3 effective theory.

  
Several Complex Variables Seminar,  243 Altgeld Hall,  12:00 p.m.
  
Jae-Seong Cho (Graduate Student, UIUC)
Multiplicities for holomorphic mappings (cont.)

  
Analytic and Elementary Number Theory,  243 Altgeld Hall,  1:00 p.m.
Favorite conjectures in number theory, II
  
Abstract: A follow-up to a popular seminar session held a few weeks ago, in which members of the audience presented some of their own favorite conjectures. Anyone who has not given a presentation during the first round is encouraged to present his/her favorite conjecture in a short talk of 5 - 10 minutes (or less).

  
Group Theory,  347 Altgeld Hall,  1:00 p.m.
  
Kim Whittlesey (visiting Assistant Professor, UIUC)
Garside groups and Bestvina's normal form complex, II
  
Abstract: Joint with R. Charney, J. Meier. A Garside group is a group admitting a finite lattice generating set. Using techniques developed by Bestvina for Artin groups of finite type, we construct K(G,1) for Garside groups. The universal covers of these K(G,1)s have Bestvina's weak non-positive curvature condition.

  
RAP on Noncommutative Lp spaces,  345 Altgeld Hall,  1:00 p.m. (cont. at 3:00 p.m.)
TBA

  
Algebraic Number Theory,  241 Altgeld Hall,  2:00 p.m.
  
Nigel Boston (Associate Professor, UIUC)
Galois actions on trees
  
Abstract: The theory of Galois actions on p-adic vector spaces has been a very important and successful one, culminating for instance in the recent proof of Fermat's Last Theorem. There is an equally viable theory of Galois actions on trees, that is barely touched. This talk will give an introduction to how the theory is being developed and give four examples that have arisen recently in the work of various mathematicians. The speaker will keep the subject matter elementary and accessible.

  
Analysis Seminar,  243 Altgeld Hall,  2:00 p.m.
  
Jorge Rivera-Noriega (Doob Postdoc, UIUC)
Parabolic measure in non-cylindrical domains
  
Abstract: We shall survey some recent results on absolute continuity of the ``harmonic meansure'' corresponding to a differential operator of parabolic type, with respect to the ``surface measure'' on non-cylindrical domains.

  
Knot Theory RAP,  345 Altgeld Hall,  2:00 p.m.
  
Elizabeth Denne (Graduate Student, UIUC)
Torus knots
  
Abstract: This talk will discuss presentations of knot groups, beginning with Rolfsen's approach to the fundamental group of the complement of a torus knot and ending with Wirtinger presentations.

  
RAP on Research Problems in Coloring Theory and Extremal Combinatorics,  241 Altgeld Hall,  3:00 p.m.
Research Problems in Combinatorics

  
Commutative Ring Theory Seminar,  243 Altgeld Hall,  3:00 p.m.
  
Andrew Richardson (Graduate Student, UIUC)
Applications of Co-localization to Local Homology

  
ECE Graduate Seminar,  151 Everitt Lab,  4:00 p.m.
  
Dr. Doug Kuhlman (Motorola Labs, Security Research Schaumburg, IL)
A Comparison of Elliptic Curve and RSA Public-Key Cryptography Methods
  
Abstract: The two public key cryptography methods most used today are elliptic curve and RSA. This talk will consider the trade-offs between the two systems in terms of code size and speed for use with various authentication levels. The talk will discuss current and future directions.

Bio: Doug Kuhlman graduated from Wartburg College in 1995 with majors in math, computer science, and religion. He received his Ph.D. in mathematics (with an emphasis in algebraic number theory) from the University of Illinois at Urbana-Champaign in 2000. He currently works at Motorola in Schaumburg, IL doing security research.


  
Mathematics Colloquium,  245 Altgeld Hall,  4:00 p.m.
  
Tomasz Luczak (Adam Mickiewicz University, Poznan, Poland and Emory University, Atlanta, Georgia)
Sum-Free Sets
  
Abstract: A subset of A of a semigroup is sum-free if it contains no solutions to the equation x+y=z. In the talk we present some open problems and recent results concerning the structure and the number of sum-free subsets of natural numbers and abelian groups
Refreshments at 3:15 p.m. in Room 321 Altgeld Hall


FRIDAY, OCTOBER 12

  
RAP ``Etale cohomology",  159 Altgeld Hall,  10:00 a.m.
  
David Gepner (Graduate Student, UIUC)
Comparing Cech and etale cohomology

  
RAP - Conformal invariance, intersection exponents and critical percolation,  145 Altgeld Hall,  4:00 p.m.
  
Robert Bauer (Assistant Professor, UIUC)
Intersection exponents for planar Brownian motion, IV

  
Model Theory Seminar,  141 Altgeld Hall,  4:00 p.m.
  
Thomas Rohwer (Graduate Student, UIUC)
Module definable sets in a field of Laurent series (part V)
  
Abstract: Let k be a finite field of characteristic p, K = k((x)) the field of Laurent series over k, and R = K[F] the ring of twisted polynomials over K with respect to the commuting relation Fl = lp F for all l in K. K is a left R module using the natural action of K on K and letting F act as l® lp. Some results on the structure of solution sets of linear equations (and projections of these) in the module K will be presented.

File translated from TEX by TTH, version 2.01.
On 5 Oct 2001, 14:53.