Weekly Calendar

October 29 - November 2, 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 29

  
RAP ``Etale cohomology'',  159 Altgeld Hall,  10:00 a.m.
  
David Murphy (Graduate Student, UIUC)
Principal homogeneous spaces

  
Special Seminar,  331 Altgeld Hall,  2:00 p.m.
  
John Klein (Wayne State Univ)
Poincare duality spaces and manifolds
  
Abstract: In this lecture I will define Poincare spaces, explain what they were set up to do (classify manifolds), and describe their tangential properties. I will then show how to construct examples of Poincare spaces which do not have the homotopy type of manifolds.

  
Special Seminar,  331 Altgeld Hall,  3:15 p.m.
  
John Klein (Wayne State Univ)
The stable approach
  
Abstract: Using stable techniques, I will show how to reconstruct the tangential theory using a new tool: the dualizing spectrum of a topological group.

  
Math 400 - Introduction to Graduate Mathematics,  245 Altgeld Hall,  4:00 p.m.
  
John D'Angelo (Professor, UIUC)
Complex Analysis in Several Variables: Analysis, Geometry and Algebra

  
VIGRE: Math 500,  243 Altgeld Hall,  4:00 p.m.
No meeting this week


TUESDAY, OCTOBER 30

  
Symplectic and Contact Geometry RAP,  143 Henry Bldg,  10:00 a.m.
  
S. Tolman (Associate Professor, UIUC)
Complexity 1 Hamiltonian torus actions: technical issues
  
Abstract: We will discuss technical issues involved in the classification of complexity 1 Hamiltonian torus actions.

  
Max Newman Topology,  345 Altgeld Hall,  11:00 a.m.
  
John Klein (Wayne State Univ)
Embedding theory of Poincare spaces: I
  
Abstract: In this lecture I will describe the current state of affairs in the theory of Poincare embeddings.

  
RAP ``Spaces of non-positive curvature'',  243 Altgeld Hall,  11:00 a.m.
  
Kim Whittlesey (Visiting Assistant, Professor, UIUC)
The Flat Torus Theorem (cont.)
  
Abstract: We will show that a proper semi-simple action of a free abelian group of rank n on a CAT(0) space X always corresponds to a translation action of this group on some n-dimensional Euclidean subspace of X. Further algebraic properties of free abelian subgroups of groups acting by isometries on CAT(0) spaces will be analyzed.

  
Probability and Statistics Seminar,  2 Illini Hall,  11:00 a.m.
No meeting this week

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

  
Quantum Information Science Seminar,  280 Materials Research Laboratory,  12:00 p.m.
  
Daniel F. V. James (Theoretical Division, Los Alamos)
Beam me up, Charlie: Teleportation of Quantum Bits in fact and fiction
  
Abstract: I will talk about the notion of qubit teleportation (i.e. involving two-level quantum systems, as opposed to harmonic oscillator modes). We will give two analyses of this idea, namely the original algebraic analysis, and a more recent quantum circuit analysis due to Mermin (which is a nice illustration of some of the techniques in this sort of analysis.) I will mention briefly experimental realizations and I will also discuss some of our recent attempts to quantify entanglement via teleportation fidelity. Some relevant papers:

``Teleporting an unknown quantum state via dual classical and Einstein-Podolosky-Rosen Channels,'' Bennett C.H, Brassard G., Crepeau C., Josza R., Peres A., Wootters W.K., Physical Review Letters, v. 70, pp. 1895-1899, MAR 29, 1993.

``Experimental realization of teleporting an unknown pure quantum state via dual classical and Einstein-Podolsky-Rosen channels,'' Boschi D., Branca S., DeMartini F., Hardy L., Popescu S., Physical Review Letters, v. 80, pp. 1121-1125, FEB 9, 1998 (Received 28 July 1997).

``Experimental quantum teleportation,'' Bouwmeester D., Pan J.W., Mattle K., Eibl M., Weinfurter H., Zeilinger A., Nature v. 390, pp. 575-579, DEC 11, 1997 (received 16 October 1998).

``Complete quantum teleportation using nuclear magnetic resonance,'' Nielsen MA, Knill E, Laflamme R, Nature, v. 396 pp. 52-55 NOV 5, 1998.

  
Analytic and Elementary Number Theory,  243 Altgeld Hall,  1:00 p.m.
More favorite proofs and/or theorems
  
Abstract: A continuation of last Thursday's seminar session, in which members of the audience presented their favorite proof in a short talk of 5 - 10 minutes, but with the scope expanded to include presentations of favorite theorems, with or without proofs.

  
Differential Geometry Seminar,  347 Altgeld Hall,  1:00 p.m.
  
John Klein (Wayne State Univ)
Embedding theory of Poincare spaces: II
  
Abstract: A continuation. I'll explain my work with Goodwillie.

  
Logic Seminar,  241 Altgeld Hall,  1:00 p.m.
  
Slawomir Solecki (Associate Professor, UIUC)
Embedding E1 in the coset equivalence relation (cont.)
  
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.

  
Algebraic Geometry Seminar,  159 Altgeld Hall,  2:00 p.m.
  
Rahul Pandharipande (Caltech)
Gromov-Witten Invariants and Completed Cycles
  
Abstract: I will talk about the Gromov-Witten theory of the Riemann sphere. The main result is a connection between descendent integrals in GW theory and completed cycles arising in the theory of symmetric functions. A link to the Toda equation will also be made. This is joint work with A. Okounkov.
NOTE UNUSUAL DAY AND LOCATION

  
Geometric Potpourri Seminar,  243 Altgeld Hall,  2:00 p.m.
  
George Francis (Professor, UIUC)
Navigating Virtual Environments II
  
Abstract: How to navigate a virtual environment and other problems addressed by the _illiMath2001_ REU-students last summer required some practical, if elementary geometrical insights. This seminar concludes a report on some of these. In particular, I will present the real-time interactive animations involving the Bishop frame. If time permits, I will solicit some ideas for future student projects.

  
Motivic Cohomology Seminar,  143 Henry Bldg,  2:00 p.m.
  
Sung Myung (Graduate Student, UIUC)
The regulator map for motivic cohomology using the dilogarithm function

  
Stochastic and Nonlinear Analysis,  347 Altgeld Hall,  2:00 p.m.
  
Yangsuk Ko (DPSD Postdoc, UIUC )
Beauty of the Lawrence-Doniach system-a coupled Ginzburg-Landau system for layered superconductors
  
Abstract: We consider a coupled Ginzburg-Landau system, so called the Lawrence-Doniach system for layered superconductors such as most high-temperature superconductors. We prove an existence result and a maximum principle of its solutions and then improve the regularity of the solution in a divergence free gauge by combining standard elliptic regularity theory with results on single layer potential. Next, we analytically show the existence of a critical field, [`h] such that when the absolute value of an applied magnetic field is greater than [`h], the normal (nonsuperconducting) state is the only solution to the Lawrence-Doniach system. Also, we introduce an anisotropic Ginzburg-Landau model and then show that as the layer spacing tends to zero, the Lawrence-Doniach system converges to the anisotropic Ginzburg-Landau system in an appropriate sense. Finally, we estimate [`h]. As k®¥ we derive [`h] = O(k) for both of the Lawrence-Doniach system and the anisotropic Ginzburg-Landau system.

  
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.
No meeting this week

  
Graph Theory and Combinatorics,  241 Altgeld Hall,  3:00 p.m.
  
Diane Donovan (University of Queensland, Australia)
Critical sets and latin trades
  
Abstract: Let L be a latin square of order n, and let T be a partial latin square contained in L. If there is a latin square M of order n distinct from L such that LÇM = T, then L\T is said to be a latin trade. For a given latin square L, it is possible to identify a subset of entries, termed a critical set, that intersects all latin trades in L and is minimal with respect to this property. In this talk I shall review known results on the sizes of critical sets and techniques used to construct critical sets. Stinson and van Rees showed that under certain circumstances, critical sets in latin squares R and S can be used to identify critical sets in the direct product R×S. In the later part of this talk I will discuss generalizations of their results.

  
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.
  
Dominika Polkowska (Graduate Student, UIUC)
The structure of Baire class 1 functions



WEDNESDAY, OCTOBER 31

  
RAP ``Etale cohomology",  159 Altgeld Hall,  10:00 a.m.
  
David Murphy (Graduate Student, UIUC)
Principal homogeneous spaces (cont.)

  
Decision, Control, and Optimization Seminar,  B02 Coordinated Science Lab,  3:00 p.m.
  
Dimitris Hristu (Mechanical Engineering, University of Maryland, College Park)
Control with Limited Communication
  
Abstract: Control and communication issues are traditionally decoupled in discussions of decision and control problem because this simplifies the analysis and generally works well for classical models. This fundamental assumption deserves re-examination as control applications spread into areas such as smart structures, communication networks, formations of robots and autonomous vehicles. In such ``distributed'' systems, the availability of a ``rich'' set of sensors and actuators comes at a price: sensors and actuators must ``share the attention'' of a controller, making lack of time as important a constraint as lack of computational power. As a result, simultaneous communication among components involves restrictive - if not unrealistic - assumptions, underscoring the need for analytical tools that bridge control and communication in modern engineering systems. Starting from a simple model for network-controlled dynamical systems, I will explore the interplay of control and communication by revisiting two classical problems in stabilization and trajectory tracking, this time for systems whose components must share limited computing or communication resources. In each case, I will propose ways of quantifying ``attention'' in the context of a network-controlled system and illustrate the effects of communication constraints on the system's overall performance. Time permitting, I will present experimental results from applications of this work in robotics and dexterous manipulation.

  
RAP on Quantum Cohomology,  160 English Bldg,  3:00 p.m.
  
Artur Elezi (Brigham Young University)
Chapter 5

  
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, IV

  
RAP - Conformal invariance, intersection exponents and critical percolation,  145 Altgeld Hall,  4:00 p.m.
  
Robert Bauer (Assistant Professor, UIUC)
Conjectures on intersection exponents

  
Information Protection Seminar,  114 Coordinated Science Lab,  4:30 p.m.
No meeting this week



THURSDAY, NOVEMBER 1

  
Math - Physics (BCDE) Lunch Seminar,  6-110 Engineering Science Bldg,  12:05 p.m.
No meeting this week

  
Several Complex Variables Seminar,  243 Altgeld Hall,  12:00 p.m.
  
Alex Tumanov (Associate Professor, UIUC)
Foliations of CR manifolds by complex curves

  
Analytic and Elementary Number Theory,  243 Altgeld Hall,  1:00 p.m.
  
Bruce Berndt (Professor, UIUC)
Generalization of a result of Ramanujan first proved by an uncle of one of Paul Bateman's Ph.D. students (joint work with A. Zaharescu)

  
Group Theory,  347 Altgeld Hall,  1:00 p.m.
  
Jon McCammond (Professor, Texas A&M)
Algorithmic aspects of nonpositive curvature
  
Abstract: A metric simplicial complex is a simplicial complex in which constant curvature metrics (with identical curvature constants) have been consistently assigned to each simplex. If such a complex has a metric of nonpositive curvature in the sense of Gromov, then a number of consequences about the structure of the fundamental group follow immediately. Until recently there were very few cases where it was possible to determine whether a given finite metric simplicial complex is nonpositively curved. In this talk we will discuss a recent algorithm to decide this question. Examples, extensions, and implementations will be discussed as time permits.

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

  
Special Analysis Seminar,  345 Altgeld Hall,  1:00 p.m.
  
Narcisse Randrianantoinina (Professor, Miami University-Oxford, Ohio)
Non commutative martingale transforms
  
Abstract: Following the lead of Pisier and Xu for the case 1 < p < ¥, we will discuss the appropriate martingale transform inequalities for the case p = 1.
Please note that the there will be a continuation of Narcisses's talk at 3:00 p.m.

  
Algebraic Geometry Seminar,  347 Altgeld Hall,  2:00 p.m.
  
Artur Elezi (Brigham Young)
Virtual Classes of Convex and Concave Varieties and Mirror Theorems
  
Abstract: Let Y be the zero locus of a regular section of a vector bundle V on a projective manifold X. We give a proof of a conjecture by Cox, Katz, and Y-P.Lee on the relation of the genus zero virtual classes of X and Y. We discuss some consequences of this on the mirror theorems. Time permitting, we will see a similar picture in the case when Y is a submanifold of X with a concave (negative) normal bundle.

  
Algebraic Number Theory,  241 Altgeld Hall,  2:00 p.m.
  
Kiran Kedlaya (NSF Postdoc, UC-Berkeley)
A p-adic local monodromy theorem

  
Analysis Seminar,  243 Altgeld Hall,  2:00 p.m.
  
Steve Hofmann (University of Missouri-Columbia)
The square root problem of Kato
  
Abstract: We discuss the history, and recent solution, of the square root problem of T. Kato, concerning the square root of a divergence form elliptic operator with complex, bounded measurable coefficients.

  
Knot Theory RAP,  345 Altgeld Hall,  2:00 p.m.
  
John Sullivan (Associate Professor, UIUC)
Rational tangles and two-bridge knots (cont.)
  
Abstract: The bridge number of a knot was related by Milnor to its total curvature. Most (small) alternating knots have bridge number two. This important class can be best understood, following Conway, as numerators of rational tangles. These tangles, generated from the zero tangle by two simple moves, are in one-to-one correspondance with rational numbers, and are related to their continued fractions.

  
Commutative Ring Theory Seminar,  243 Altgeld Hall,  3:00 p.m.
  
Phillip Griffith (Professor, UIUC)
The Syzygy Theorem

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

  
Mathematics Colloquium,  314 Altgeld Hall,  4:00 p.m.
  
Kristin Lauter (Microsoft Research)
Curves over Finite Fields and applications to Cryptography and Coding Theory
  
Abstract: In the last 20 years, curves over finite fields have been used in a number of applied areas such as coding theory and cryptography. Goppa codes, elliptic curve cryptosystems, elliptic curve methods for factoring and primality proving, and hyperelliptic curve cryptosystems are the main examples of how curves can be used in applications. This talk will give an introduction to the use of curves in cryptography and survey some of the known algorithms in this area. Point-counting for curves and their Jacobians and methods for generating curves with a known number of points are two of the important issues for cryptography. I will explain some recent progress in these areas.
Refreshments at 3:15 p.m. in Room 321 Altgeld Hall



FRIDAY, NOVEMBER 2

  
RAP ``Etale cohomology",  159 Altgeld Hall,  10:00 a.m.
  
David Murphy (Graduate Student, UIUC)
Principal homogeneous spaces (cont.)

  
RAP - Conformal invariance, intersection exponents and critical percolation,  145 Altgeld Hall,  4:00 p.m.
  
Robert Bauer (Assistant Professor, UIUC)
Universality I

  
Model Theory Seminar,  141 Altgeld Hall,  4:00 p.m.
  
James Tyne (Graduate Student, UIUC)
Valuation and Residue Properties for power bounded theories
  
Abstract: Suppose that R is a model of some extension of RCF, and that Ráañ is an elementary extension of R, and that these models are equipped with valuations, v,w. The Valuation Property asserts that if the value groups are different, then there is r in R such that w(a-r) is not in the value froup of R. The Residue Property asserts that if the residue fields are different, then there are c,d in R such that ca-d witnesses this difference. I will define these terms, state these properties more precisely, and show that these properties hold for o-minimal power bounded theories.

File translated from TEX by TTH, version 2.01.
On 26 Oct 2001, 14:37.