# Mathematical Sciences Research Institute

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1. # GTC Graduate Seminar: Partitionable Extenders: A Combinatorial Interpretation of the h-vector

Location: MSRI: Baker Board Room
Speakers: Joseph Doolittle (University of Kansas)

The h-vector of a pure simplicial complex is of critical importance to combinatorialists and algebraists. When the complex is partitionable, a combinatorial interpretation for the h-vector is well known. In joint work with Bennet Goeckner and Alexander Lazar, we introduce a new construction which allows for an interpretation of the h-vector as an error term between a partitionable complex and a partitionable relative complex. This construction is inductive and is not minimal. We will briefly discuss minimality and some other issues that arise.

Updated on Dec 06, 2017 01:17 PM PST
2. # GTC Main Seminar: On the treewidth of triangulated three-manifolds

Location: MSRI: Simons Auditorium
Speakers: Jonathan Spreer (Freie Universität Berlin)

In graph theory, as well as three-manifold topology, a wide range of parameters exist to decide how "simple", or "thin", a given graph or three-manifold is. These width-type parameters, such as pathwidth or treewidth for graphs, or the concept of thin position for three-manifolds, play an important role when studying algorithmic problems in the field: There exist several topological problems -- some of them known to be computationally hard in general -- which become solvable in polynomial time as soon as the dual graph of the input triangulation has bounded tree width.
In view of such algorithmic results, the question of whether there exists an explicit link between combinatorial concepts such as treewidth (applicable to a single input triangulation of a given three-manifold M) and results in three-manifold topology (applicable to all possible triangulations of M) has repeatedly been asked by researchers working in the computational branch of three-manifold topology.
In this talk I will present such a link, stating that there exist families of three-manifolds not admitting triangulations of bounded treewidth.

Updated on Dec 08, 2017 08:44 AM PST
3. # GFA Main Seminar: Ideals in L(L_p)

Location: MSRI: Simons Auditorium
Speakers: William Johnson (Texas A & M University)
I'll discuss the Banach algebra structure of the spaces of bounded linear operators on ell_p and L_p:=L_p(0,1).
The main new results are

1. The only non trivial closed ideal in L(L_p), for 1 <= p < infty, that
has a left approximate identity is the ideal of compact operators (joint
with N. C. Phillips and G. Schechtman).

2. There are infinitely many; in fact, a continuum; of closed ideals in
L(L_1) (joint with G. Pisier and G. Schechtman).

The second result answers a question from the 1978 book of A. Pietsch,
Operator ideals".
Updated on Dec 05, 2017 11:06 AM PST
4. # GFA Main Seminar: Ideals in L(L_p)

Location: MSRI: Simons Auditorium
Speakers: William Johnson (Texas A & M University)
I'll discuss the Banach algebra structure of the spaces of bounded linear operators on ell_p and L_p:=L_p(0,1).
The main new results are

1. The only non trivial closed ideal in L(L_p), for 1 <= p < infty, that
has a left approximate identity is the ideal of compact operators (joint
with N. C. Phillips and G. Schechtman).

2. There are infinitely many; in fact, a continuum; of closed ideals in
L(L_1) (joint with G. Pisier and G. Schechtman).

The second result answers a question from the 1978 book of A. Pietsch,
Operator ideals".
Updated on Dec 05, 2017 11:06 AM PST

1. # GTC Main Seminar: GTC Farewell Seminar

Location: MSRI: Simons Auditorium

Several short talks by members of the GTC program on their work during the semester.

Updated on Dec 08, 2017 08:45 AM PST
2. # GFA Young Researchers Seminar: A solution to the problem of bodies with congruent sections or projections

Location: MSRI: Simons Auditorium
Speakers: Ning Zhang (MSRI - Mathematical Sciences Research Institute)

In this talk, we will construct two convex bodies K and L, such that their projections K|H, L|H onto every subspace H are congruent, but nevertheless, K and L do not coincide up to a translation or a reflection in the origin. This gives a negative answer to an old conjecture posed by Nakajima and Suss.

Created on Dec 05, 2017 11:48 AM PST
3. # GFA Main Seminar: Are convex functions special?

Location: MSRI: Simons Auditorium
Speakers: Yanir Rubinstein (University of Maryland)

Legendre duality is inherently a "real" object. Is there a complex analogue of Legendre? In our quest to find such an object, Berndtsson, Cordero-Erausquin, Klartag, and I revisit the « canonical'' role of convex functions, finding many similar classes of functions, all subsets of the space of plurisubharmonic functions. This turns out to have ties to several foundational works in interpolation theory going back to Calderon, Coifman, Cwikel, Rochberg, Sagher, and Weiss, as well as in complex analysis/geometry going back to Alexander--Wermer, Slodkowski, Moriyon, Lempert, Mabuchi, Semmes, and Donaldson.

Created on Dec 05, 2017 11:49 AM PST
4. # GTC Visions Seminar: GTC Farewell Visions

Location: MSRI: Simons Auditorium

Several short talks by members of the GTC program on their work during the semester.

Updated on Dec 08, 2017 08:45 AM PST
5. # GFA Main Seminar: Some new approaches to the heavy hitters problem

Location: MSRI: Simons Auditorium
Speakers: Jelani Nelson (Harvard University)
In the 'frequent items' problem one sees a sequence of items in a stream (e.g. a stream of words coming into a search query engine like Google) and wants to report a small list of items containing all frequent items. In the 'change detection' problem one sees two streams, say one from yesterday and one from today, and wants to report a small list of items containing all those whose frequencies changed significantly. For both of these problems, we would like algorithms that use memory substantially sublinear in the length of the stream.
We describe new state-of-the-art solutions to both problems. For the former, we make use of ideas familiar to this community such as chaining methods to control the suprema of Rademacher processes to develop an algorithm BPTree with provably near-optimal memory consumption. For the latter, ideas familiar to this community also pop up (e.g. isoperimetry and Cheeger's inequality) in the course of developing the first algorithm to simultaneously achieve asymptotically optimal space, fast query and update time, and high success probability (over the random coins flipped by the algorithm).
Based on joint works with Vladimir Braverman, Stephen Chestnut, Nikita Ivkin, Kasper Green Larsen, Huy Le Nguyen, Mikkel Thorup, Zhengyu Wang, and David P. Woodruff
Updated on Dec 08, 2017 09:24 AM PST
6. # GFA Main Seminar: Projection theorem in Banach spaces

Location: MSRI: Simons Auditorium
Speakers: Marianna Csornyei (University of Chicago)

We study tangential properties of planar curves and demonstrate the failure of the Besicovitch-Federer projection theorem in Banach spaces. Based on joint works with David Bate and Bobby Wilson.

Updated on Dec 08, 2017 09:24 AM PST
7. # The Bowen Lectures

Location: UC Berkeley
Speakers: Avi Wigderson
Created on Aug 21, 2017 02:36 PM PDT
8. # The Bowen Lectures

Location: UC Berkeley
Speakers: Avi Wigderson
Created on Aug 21, 2017 02:36 PM PDT
9. # The Bowen Lectures

Location: UC Berkeley
Speakers: Avi Wigderson
Created on Aug 21, 2017 02:36 PM PDT
10. # Seminar Sequence

Location: MSRI: Simons Auditorium
Created on Aug 31, 2017 03:27 PM PDT

1. # SeminarGTC Postdoc Seminar: Non-spanning lattice 3-polytopes

Updated on Nov 29, 2017 11:04 AM PST
2. # SeminarGFA Postdoc Seminar: On illumination conjecture and the local maximality of the cube

Updated on Dec 01, 2017 08:55 AM PST
3. # SeminarGFA Main Seminar: Pisier's cotype dichotomy problem revisited

Updated on Nov 20, 2017 09:11 AM PST
4. # SeminarGFA Main Seminar: Pisier's cotype dichotomy problem revisited

Updated on Nov 20, 2017 09:11 AM PST
5. # SeminarGTC Visions Seminar: Some GTC conjectures I loved, but did not love me back

Updated on Dec 01, 2017 09:22 AM PST
6. # SeminarLattice Points Working Group: Flatness theorem via geometric functional analysis

Updated on Dec 01, 2017 10:08 AM PST
7. # SeminarGFA Main Seminar: Local $L^p$-Brunn--Minkowski inequalities for $p < 1$

Updated on Dec 01, 2017 10:11 AM PST
8. # SeminarCombinatorial Fixed Point Theorems Working Group: Diameter of convex sets via graphs with large girth and small independence number

Updated on Nov 30, 2017 08:43 AM PST
9. # SeminarGFA Main Seminar: Local $L^p$-Brunn--Minkowski inequalities for \$p <

Updated on Dec 01, 2017 10:11 AM PST
10. # SeminarGTC Main Seminar: Flow polytopes with Catalan Volumes

Created on Dec 04, 2017 03:00 PM PST
11. # SeminarGTC Graduate Seminar: Ehrhart polynomial of a polytope plus scaling zonotope

Updated on Nov 29, 2017 08:52 AM PST
12. # SeminarUC Berkeley Colloquium: Algebraic Structures on Polytopes

Updated on Nov 20, 2017 12:10 PM PST
13. # SeminarGFA Main Seminar: Duality of floating bodies and illumination bodies

Updated on Nov 27, 2017 08:43 AM PST
14. # SeminarGFA Main Seminar: On the geometry of projective tensor products

Updated on Nov 27, 2017 08:43 AM PST
15. # SeminarGTC Visions Seminar: Continuous Matroids revisited

Updated on Nov 22, 2017 02:03 PM PST
16. # SeminarGFA Young Researchers Seminar: Iterative Methods for Solving Factorized Linear Systems

Updated on Nov 22, 2017 08:41 AM PST
17. # SeminarGFA Main Seminar: The minimum Euclidean norm point in a polytope: Wolfe's method is exponential

Updated on Nov 27, 2017 08:42 AM PST
18. # SeminarGTC Main Seminar: Spanning lattice polytopes and the Uniform position principle

Updated on Oct 30, 2017 11:24 AM PDT

Created on Aug 18, 2017 11:45 AM PDT
20. # SeminarGFA Young Researchers Seminar: Gaussian concentration and random unconditional structure

Updated on Nov 16, 2017 01:44 PM PST
21. # SeminarGFA Main Seminar: Sidon Sets and Random Matrices

Updated on Nov 13, 2017 03:15 PM PST
22. # SeminarTwo Famous Betting Systems

Updated on Nov 21, 2017 11:00 AM PST
23. # SeminarGFA Main Seminar: Sidon Sets and Random Matrices

Updated on Nov 13, 2017 03:15 PM PST
24. # SeminarGTC Main Seminar: On the Topology of Steel

Updated on Oct 30, 2017 11:22 AM PDT

Created on Aug 18, 2017 11:45 AM PDT
26. # SeminarLattice Points Working Group: Lattice points on Convex Bodies

Updated on Nov 15, 2017 08:43 AM PST
27. # SeminarUC Berkeley Colloquium: What is quantum chaos?

Updated on Nov 09, 2017 08:52 AM PST
28. # SeminarUC Berkeley Colloquium: The Global Histories of Mathematics

Updated on Nov 02, 2017 01:42 PM PDT
29. # SeminarGFA Main Seminar: Borell’s formula and applications

Updated on Nov 03, 2017 11:16 AM PDT
30. # SeminarGFA Main Seminar: Borell’s formula and applications

Updated on Nov 03, 2017 11:15 AM PDT
There are more then 30 past seminars. Please go to Past seminars to see all past seminars.