Weekly Calendar

October 1-5, 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 1

  
RAP ``Etale cohomology'',  159 Altgeld Hall,  10:00 a.m.
  
Sean Sather-Wagstaff (VIGRE Postdoc, UIUC)
Cohomology on a site

  
Math 400 - Introduction to Graduate Mathematics,  245 Altgeld Hall,  4:00 p.m.
  
Nigel Boston (Associate Professor, UIUC)
How Algebra Enters Number Theory


TUESDAY, OCTOBER 2

  
Symplectic and Contact Geometry RAP,  143 Henry Bldg,  10:00 a.m.
  
Hui Li (Graduate Student, UIUC)
Semi-free Hamiltonian circle actions on 6 dimensional symplectic manifolds
  
Abstract: I consider such symplectic manifolds with isolated fixed points and fixed surfaces. I mainly restrict attention to the case when H2(M) < 3. For the simply connected manifolds, I give a classification up to diffeomorphism, for the non-simply connected ones, I prove that their cohomology rings and Chern classes are uniquely determined.

  
Max Newman Topology,  345 Altgeld Hall,  11:00 a.m.
  
Matthew Ando (Assistant Professor, UIUC)
The sigma orientation is H-infinity

  
RAP ``Spaces of non-positive curvature'',  243 Altgeld Hall,  11:00 a.m.
  
Elizabeth Denne (Graduate Student, UIUC)
Knot groups and CAT(0) complexes
  
Abstract: We will show that the fundamental group of the complement of a prime alternating knot can be realized as the fundamental group of a finite non-positively curved square complex.

  
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.
  
Jae-Seong Cho (Graduate Student, UIUC)
Intersection multiplicities for holomorphic mappings

  
Quantum Information Science Seminar,  280 Materials Research Laboratory,  12:00 p.m.
  
John Tucker (Professor, Department of Electrical and Computer Engr., UIUC)
Silicon Quantum Logic
  
Abstract: Silicon quantum computers utilizing individual phosphorous donor qubits have been proposed; and experimental efforts in this direction are currently underway in Australia and Los Alamos as well as here at Illinois. This talk will describe the basic ideas underlying this type of solid-state quantum computer, together with the techniques employed for STM positioning of individual donors followed by low-temperature silicon overgrowth. These processes also appear well suited to fabrication of more general atom-scale integrated circuits, and one possibility-integration of single-electron output transistors along with P-atom qubits-will be described. References:

[1]. B.E. Kane, ``A silicon-based nuclear spin quantum computer," Nature 393, 133-138 (1998).

[2]. J. R. Tucker and T.-C. Shen, ``Prospects for atomically ordered device structures based on STM lithography," Solid State Electronics 42, 1061-1067 (1998).

[1]. R. Vrijen, E. Yablonovitch, K. Wang, H.W. Jiang, A. Balandin, V. Roychowdhury, T. Mor, and D. DiVincenzo, ``Electron spin resonance transistors for quantum computing in silicon-germanium hetero-structures," Phys. Rev. A 62, 12306-1-12306-10 (2000).

  
Analytic and Elementary Number Theory,  243 Altgeld Hall,  1:00 p.m.
  
Ae Ja Yee (Visiting Assistant Professor, UIUC)
Continued fractions with three limit points, I
  
Abstract: We report on some recent joint work with George Andrews, Bruce Berndt, Jaebum Sohn and Alexandru Zaharescu, motivated by an enigmatic entry in Ramanujan's lost notebook, in which he claimed that a certain q-continued fraction possesses three limit points. We develop a mechanism which can be used to explicitly produce a large class of continued fractions having exactly three limit points.

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

  
Logic Seminar,  241 Altgeld Hall,  1:00 p.m.
  
Wai Yan Pong (Doob Postdoc, UIUC)
Uniform bounds on Morley Rank for definable families in Differentially Closed Fields.
  
Abstract: We will present a result concerning upper bounds of Morley Rank of fibers in a definable family in m-DCF. There are some interesting applications of Hilbert polynomials in this situation. We will also discuss a simplification to a result in my talk last week and show that RU(G)=RM(G) for definable groups in m-DCF.

  
Geometric Potpourri Seminar,  243 Altgeld Hall,  2:00 p.m.
  
Clark Kimberling (Professor, University of Evansville)
Topics in Triangle Geometry
  
Abstract: We'll begin with an overview of recent and forthcoming phenomena that carry current waves in triangle geometry: Hyacinthos, Forum Geometricorum, The Triangle Book, and ETC. Many of the waves consist of new results about 19th century cubic curves, including the Darboux and Lucas cubics. We'll discuss these two in particular and then turn to a possibly new class of cubics. Their main representative is the locus of a point X for which the cevian triangle of X and the cevian triangle of the isogonal conjugate of X have equal area. Among sixteen points proved to lie on this ëqual-area cubic" are the 1st and 2nd Brocard points.

  
Stochastic and Nonlinear Analysis,  347 Altgeld Hall,  2:00 p.m.
  
T. Kulcyzcki (University of Wroclaw)
Stable processes have thorns

  
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 RAP,  243 Altgeld Hall,  3:00 p.m.
  
Sean Sather-Wagstaff (VIGRE Postdoc, UIUC)
Local Chern Characters (cont.)
http://www.math.uiuc.edu/ ssather/MATH/crt_fa01.html

  
Decision, Control and Optimization Seminars,  B02 Coordinated Science Laboratory,  3:00 p.m.
  
Ioan D. Landau (Laboratoire d'Automatique de Grenoble, ENSIEG, France)
Identification in Closed-Loop: A Powerful Design Tool (better design models, simpler controllers)
  
Abstract: The talk will focus on system identification in closed-loop as a tool for obtaining improved models for control design and reduced order controllers. The methodology for plant model identification in closed loop will be briefly surveyed and illustrated by experimental results. The interaction with robust control design will be emphasized. The use of identification in closed loop as a tool for controller reduction will be discussed and illustrated by experimental results. Some general remarks and directions of current research will conclude the talk.

  
Graph Theory and Combinatorics,  241 Altgeld Hall,  3:00 p.m.
  
Peter Hamburger (Indiana-Purdue University at Fort Wayne)
Saturated chains, paths in posets, and combinatorial geometry
  
Abstract: We will study the structure of saturated chains and edge-disjoint paths in partially ordered sets. Using this study, we will learn how to create pretty symmetrical drawings. In this journey, there will be some geometry, number theory, and group theory, and combinatorial topics such as codes, dual graphs, and symmetric, saturated, and maximal chains. The results will answer a conjecture of B. Grünbaum that goes back to D. W. Henderson.

  
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

  
Special Seminar,  245 Altgeld Hall,  4:00 p.m.
  
Joris van der Hoeven (CNRS, Universiti Paris-Sud, Orsay, France)
GNU TeXmacs: A User Friendly Mathematical Text Editor
  
Abstract: We will give a software demonstration of the free text editor GNU TeXmacs. The program allows you to compose structural documents with mathematical formulas. The typesetting quality of the final printed documents is comparable to TeX/LaTeX. Yet, the wysiwyg front end makes TeXmacs very user friendly. We will also show how to use the program as an interface to computer algebra systems. For more information about TeXmacs, please take a look at our website http://www.texmacs.org.


WEDNESDAY, OCTOBER 3

  
RAP ``Etale cohomology",  159 Altgeld Hall,  10:00 a.m.
  
Sean Sather-Wagstaff (VIGRE Postdoc, UIUC)
Cohomology on a site (cont.)

  
Algebraic Geometry RAP,  160 English Bldg,  3:00 p.m.
  
Sheldon Katz (Professor, UIUC)
Quantum Cohomology, II

  
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, I

  
Information Protection Seminar,  114 CSRL,  4:30 p.m.
  
Han Duong (Graduate Student, UIUC)
Using Efficient Endomorphisms for Faster Multiplication on Elliptic Curves
  
Abstract: The talk will touch upon the efficient computation of multiples kP of a point P. To apply the simultaneous point multiplication (SPM) technique, kP is expanded into a sum k1 P + k2 phi(P) for a suitable endomorphism phi.

  
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


THURSDAY, OCTOBER 4

  
Math - Physics (BCDE) Lunch Seminar,  6-110 Engineering Science Bldg,  12:05 p.m.
  
Yang-Hui He (Massachusetts Institute of Technology)
Toric Duality = Seiberg Duality, an Etude on D-branes and Quivers
  
Abstract: The study of world-volume gauge theories arising from D-branes probing transversely to an algebraic (space-time) singularity has been of diverse interest. New insights have been shed in string theory, field theory, phenomenology, as well as mathematics. In this talk we shall give a comprehensive overview of the techniques of probing a wide class of singularities, viz., toric singularities. We shall familiarise the audience with quivers, toric data, and a beautiful phenomenon known as toric duality.

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

  
Analytic and Elementary Number Theory,  243 Altgeld Hall,  1:00 p.m.
  
Alexandru Zaharescu (Assistant Professor, UIUC)
Continued fractions with three limit points, II
  
Abstract: See abstract for Tuesday's talk

  
Group Theory,  347 Altgeld Hall,  1:00 p.m.
  
Kim Whittlesey (visiting Assistant Professor, UIUC)
Small Gaussian groups and Bestvina's normal form complex
  
Abstract: Joint with R. Charney, J. Meier. A small Gaussian 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 small Gaussian 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.)
No meeting this week

  
Algebraic Number Theory,  241 Altgeld Hall,  2:00 p.m.
No meeting this week because of the Thirty-Ninth Annual Allerton Conference on Communication, Control, and Computing, Allerton House, Monticello, Illinois, Wednesday, October 3 - Friday, October 5.
See http://comm.csl.uiuc.edu/allerton/allerton01/

  
Analysis Seminar,  243 Altgeld Hall,  2:00 p.m.
  
Peter Loeb (Professor, UIUC)
An alternative to the classical maximal function

  
Knot Theory RAP,  345 Altgeld Hall,  2:00 p.m.
  
Nadya Shirokova (Doob Postdoc, UIUC)
Finite-type invariants of knots II

  
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)
Attached Primes of Graded Modules
http://www.math.uiuc.edu/ ssather/MATH/crt_fa01.html


  
Mathematics Colloquium,  314 Altgeld Hall,  4:00 p.m.
  
Richard Bass (Professor, Department of Mathematics, University of Connecticut)
Probability and Analysis on Fractals
  
Abstract: In this talk I will try to convince you that one can do real mathematics involving fractals. The Sierpinski carpet is the fractal one obtains by starting with the unit square, dividing it into 9 equal subsquares, removing the central square, and repeating. If one runs a reflecting Brownian motion in the n-th stage of this construction, then as n gets large, the process moves slower and slower, and the limit is degenerate. However if one renormalizes, i.e., speeds up the n-th stage, one gets a nondegenerate limit, which is Brownian motion on the Sierpinski carpet. This process has some unusual properties. For example, it scales, but not according to t1/2. Even though the process is not one dimensional, it hits points.

The rate at which one renormalizes depends on a family of eigenvalue problems. These can be related to the energy of certain harmonic functions, which in turn are related to the notion of electrical resistance from electrical circuit theory.

It is natural to consider the infinitesimal generator of Brownian motion on the Sierpinski carpet a Laplacian on the carpet, and one can then talk about the heat equation on the carpet. Good bounds can be found for the heat kernel. There are strong relations with Sobolev and Poincari inequalities.

Refreshments at 3:15 p.m. in Room 321 Altgeld Hall


FRIDAY, OCTOBER 5

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

  
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, II

  
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 IV)
  
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 28 Sep 2001, 13:35.