Calendar

Nov
22
Fri
Colloquium-Markus Pflaum (U. Colorado) @ Keller 401
Nov 22 @ 3:30 pm – 4:30 pm

Speaker: Markus Pflaum (U. Colorado)

Title: Whitney Functions, the real homotopy type of a semi-analytic set, and a
Hochschild-Kostant-Rosenberg type theorem

Abstract:
In the talk we consider semi-analytic subsets of a real analytic
manifold and their homology and real homotopy type.
It is well-known that de Rham’s Theorem does not hold true in general
for singular spaces such as semi-analytic sets.
We show that to remedy this one can replace the de Rham complex by the
Whitney-de Rham complex to compute the
singular homology of such sets. Beyond that, the Whitney-deRham complex
even determines the real homotopy type of
a semi-analytic set which extends a result by Sullivan for the de Rham
complex on smooth manifolds.
Finally, we comment on a Hochschild-Kostant-Rosenberg type theorem for
Whitney functions.
The talk is based on joint work with B. Chriestenson and J.-P.
Brasselet.

Dec
2
Mon
Master’s Defense: Ms. Erica Brown @ Keller 301
Dec 2 @ 3:00 pm – 5:00 pm
Dec
6
Fri
Colloquium: Pamela Harris (Williams)
Dec 6 @ 3:30 pm – 4:30 pm
Jan
3
Fri
Colloquium: Pamela Harris (Williams)
Jan 3 @ 3:30 pm – 4:30 pm
Jan
17
Fri
Colloquium-John Holbrook (U of Guelph) @ Keller 401
Jan 17 @ 3:30 pm – 4:30 pm

Title: Haleakala and complete polynomial bounds

Speaker: John Holbrook, U of Guelph, Ontario, Canada

Abstract: In a highly influential 1970 paper Paul Halmos drew attention to ten research problems about Hilbert space operators. Among the most stimulating was the following: find an intrinsic property of an operator T that holds iff T is similar to a contraction C. Halmos proposed that such a property might be: K(T) is finite, where K(T) is the so-called polynomial bound of T, ie the supremum of ||p(T)|| over polynomials p mapping the unit disc into itself. Many important tools were developed in response to this problem, notably by Arveson, Paulsen, Bourgain, Pisier, and Davidson. Pisier finally (c.1995) showed that the Halmos criterion must be strengthened. We’ll give an account of these developments (suitable for a general mathematical audience) leading up to a related puzzle that was resolved very recently in joint work [CGH2013] with Michel Crouzeix and Frank Gilfeather. The Hawaiian connection: [CGH2013] puts on a solid basis earlier work (c.1997) done with Frank at the Maui High Performance Computing Center.

Jan
27
Mon
Colloquium-Isaac Goldbring (U. Illinois at Chicago) @ Keller 401
Jan 27 @ 3:30 pm – 4:30 pm

Speaker: Isaac Goldbring (U. Illinois at Chicago)

Title: Existentially closed C* algebras and a conjecture of Kirchberg

Abstract: The notion of existentially closed structure is a model-theoretic generalization of the notion of algebraically closed field. A common goal in model theory is to try and understand the existentially closed objects of some axiomatizable category. In this talk, I will explain an interesting connection between the search for an existentially closed C* algebra with a certain important property (namely exactness) and a conjecture of Kirchberg concerning the ultrapower of the Cuntz algebra O_2. All relevant model theoretic and C* algebraic notions will be defined.

Jan
31
Fri
Lab-warming event
Jan 31 @ 12:30 pm – 1:30 pm

Please join us to mark the launch of the math department’s new lab!

Event: Informal gathering with food and drinks
Time: 12:30 this Friday
Place: PBRC Bekesy Building, Room A101

The address is 1993 East-West Road, a short walk from Keller (for directions see https://goo.gl/maps/yvF73).

The lab is for conducting experiments involving fluid flow as part of interdisciplinary research and teaching in applied math. This event is an opportunity to learn more about the lab and meet people across disciplines on Manoa campus.

Daisuke Takagi
Assistant Professor

Colloquium- Jonathan D. Williams (U. Georgia) @ Keller 401
Jan 31 @ 3:30 pm – 4:30 pm

Speaker: Jonathan D. Williams (U. Georgia)

Title: Smooth 4-manifolds, surface diagrams and holomorphic polygons

Abstract: The topic of smooth 4-manifolds is a long established, yet
underdeveloped one. Its mystery lies partly in its wealth of strange
examples, coupled with a lack of generally applicable tools to put
those examples into a sensible framework, or to effectively study
4-manifolds that do not satisfy rather strict criteria. I will outline
recent work that associates objects from symplectic topology, called
weak Floer A-infinity algebras, to general smooth, closed oriented
4-manifolds. As time permits, I will speculate on a “genus-g Fukaya
category of smooth 4-manifolds.”