You can access the videos from the workshop’s program page.

The Novermber 6 Center Meeting will be held in Room 402 of the Princeton Computer Science building. The schedule is given below:

10:00 – 10:45 Administrative meeting (Only for the Principal Investigators).

10:45 – 12:00 Madhur Tulsiani (abstract below)
12:00 – 1:15 Lunch + coffee break
1:15 – 2:15 Open Problems Session: Russell Impagliazzo, Valentine
Kabanets, Moni Naor, Mohan Paturi, Avi Wigderson + others
2:20 – 2:45 Short talk by Alex Kolla
2:50 – 3:15 Short talk by Alex Andoni

Abstract for Madhur Tulsiani:
Title: “Local Constraints in Combinatorial Optimization”.

I will give overview of various hierarchies which
strengthen linear and semidefinite programs by adding increasingly
larger local constraints. I will describe few techniques for arguing
about them and conclude with some open problems.

Theory lunch talk, Friday October 30:

Satisfiability Allows No Nontrivial Sparsification Unless The Polynomial-Time Hierarchy Collapses

Dieter van Melkebeek, University of Wisconsin Madison

Abstract. Consider the following two-player communication process to decide a language $L$: The first player holds the entire input $x$ but is polynomially bounded; the second player is computationally unbounded but does not know any part of $x$; their goal is to cooperatively decide whether $x$ belongs to $L$ at small cost, where the cost
measure is the number of bits of communication from the first player to the second player.

For any integer $d \geq 3$ and positive real $\epsilon$ we show that if satisfiability for $n$-variable $d$-CNF formulas has a protocol of cost $O(n^{d-\epsilon})$ then coNP is in NP/poly, which implies that the polynomial-time hierarchy collapses to the third level. The result even holds for conondeterministic protocols, and is tight as
there exists a trivial deterministic protocol for $\epsilon = 0$. Under the hypothesis that coNP is not in NP/poly, our result implies tight lower bounds for parameters of interest in several areas, including sparsification, kernelization in parameterized complexity, lossy compression, and probabilistically checkable proofs.

By reduction similar results hold for other NP-complete problems. For the vertex-cover problem on $n$-vertex $d$-uniform hypergraphs the above statement holds for any integer $d \geq 2$. The case $d=2$ implies that no NP-hard vertex deletion problem based on a hereditary graph property can have kernels consisting of $O(k^{2-\epsilon})$
edges unless coNP is in NP/poly, where $k$ denotes the size of the deletion set. Kernels consisting of $O(k^2)$ edges are known for several problems in the class, including vertex cover, bounded-degree
deletion, and feedback vertex set.

Joint work with Holger Dell.

Theory lunch talk: Friday October 23rd

Towards Polynomial Lower Bounds for Dynamic Problems

Mihai Patrascu, AT&T Labs – Research

Abstract:
We formulate a conjecture about the hardness of a certain
data-structural version of set disjointness, and show that it implies
polynomial lower bounds for many central questions in data structures.

We then show that our conjecture follows from the widely-accepted
hypothesis on the hardness of 3SUM. Ours is the first non-algebraic
reduction from 3SUM, which is a development of independent interest.

We also describe how our conjecture could be proved unconditionally,
by analyzing a certain number-on-forehead communication game.

The paper shows that in certain settings it can be computationally infeasible to verify that a financial derivative such as a collateralized default obligation (CDO) is properly constructed, in the sense that there is sufficient diversity of assets so that the derivative is not overly sensitive to some small  segment of the market.  Moreover, it may be possible to generate derivatives that are sensitive to such a small market segment, but are indistinguishable from properly diverse ones, implying an opportunity for the seller to make a profit  if he has private information that a particular segment is worth less than it appears (i.e., a “lemon”).

Several blogs also commented this paper including: Freedom to Tinker, Boing Boing, Daily Kos, In Theory,  Healthy Algorithms (including code to generate concrete computational challenges),  Lipton’s blog.

Theory lunch talk: Friday October 16th.

On the Geometry of Differential Privacy

Moritz Hardt, Princeton University

Abstract:
We consider the noise complexity of differentially private mechanisms in the setting where the user asks d linear queries f:R^n->R non-adaptively. Here, the database is represented by a vector in R^n. Proximity between databases is measured in the l1-metric.

We show that the noise complexity is determined by two geometric parameters of a convex body associated with the set of queries. Using this connection we give tight upper and lower bounds on the noise complexity of random linear queries for any d

Quantitatively, our result shows that it is necessary and sufficient to add l2-error \Theta(min{d\sqrt{\log n},d\sqrt{d}}) to achieve differential privacy. The best previous upper bound (Laplacian mechanism) gives a bound of O(d\sqrt{d}), while the best known lower bound was \Omega(d). In contrast, our lower bound is strong enough to separate differential privacy from the notion of approximate differential privacy where an upper bound of O(d) can be achieved.

Joint work with Kunal Talwar.

IAS is co-organizing with the center for computational intractability a workshop on
Pseudo-randomness in Mathematical Structures

on June 14-18.

Organizers:  Jean Bourgain, Russell Impagliazzo, Peter Sarnak and Avi Wigderson

Email:pseudo.workshop {at} gmail(.)com

See http://www.math.ias.edu/pseudo2010 for more details.

Registration to the workshop is free, but we strongly request that people register before March 7, 2009.

We encourage participants to make their hotel reservation early by calling Nassau Inn at 800-862-7728 or 609-921-7500.  A block of rooms has been reserved for participants in the workshop.

We have some limited funds for partial travel support for students - students interested in such support should fill the appropriate details in the form below and have a faculty member send a letter of support to pseudo.workshop {at} gmail(.)com   . The letter should arrive no later than March 7, 2009 and should have a subject line of “Letter of support for XX”, where  XX is the student’s full name.

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November 2-3, 2009

Organizer: Bernard Chazelle

The workshop will explore the benefits of viewing self-organizing systems, especially those occurring in nature, as “algorithms.” It will examine the possibility of building new bridges between theoretical computer science and the fields of biology, control theory, physics, engineering, and applied math, where dynamical systems have been traditionally studied. The talks will take place in the Prince William Ballroom of the Nassau Inn hotel.

Registration is free but mandatory. Online registration is closed. Walk-ins are welcome.
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Click here for program

Local information: If you plan to come to the workshop and need a hotel room, we suggest you register and reserve a room at the Nassau Inn as soon as possible. Their phone number is 1-800-862-7728 or 609-921-7500. For further information on local hotels, click here. For campus map, including parking lots and Palmer House, click here and here.

Driving and Parking information. Visitors coming to campus on weekdays from 8 am to 5 pm may park in Lot 21 near Jadwin Gymnasium. They can also use garage #3 (highest level) on Prospect Street. Place this parking pass on your dashboard. Directions to campus link here: http://www.princeton.edu/main/visiting/travel/driving/

Use this link to make reservations to an airport shuttle with Princeton University discount. For further questions not answered in this page, send us email at natalg09 {at} gmail(.)com.

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1:45 – 2:00 — Announcements.
2:00 – 2:25 — Troy Lee short talk.
2:25 – 2:50 —- Robert Tarjan short talk.

Abstract for Guy Rothblum: