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The Fifteenth Bay Area Discrete Math Day (BADMath Day) will take place on Saturday, October 20, 2007 between 10:00 AM and 5:00 PM, at the main campus of Google Inc. (the "Googleplex") in Mountain View, CA, in the Havana Tech Talk room at 900 Alta.
PLEASE NOTE: UNLIKE MOST PREVIOUS BAD MATH DAYS, YOU MUST PRE-REGISTER IN ORDER TO ATTEND. THE DEADLINE TO PRE-REGISTER IS OCTOBER 10TH. Pre-registration instructions are included below.
ALSO NOTE: the location has changed; it is no longer in building 43, but in the 900 Alta Ave. building on the east side of campus. We had to move to accommodate another event taking place in 43. See modified directions below.
BADMath Days are one-day meetings aimed at facilitating communication between researchers and graduate students of discrete mathematics around the San Francisco Bay Area. These days happen twice a year and strive to create an informal atmosphere to talk about discrete mathematics. The term "discrete mathematics" is chosen to include at least the following topics: Algebraic and Enumerative Combinatorics, Discrete Geometry, Graph Theory, Coding and Design Theory, Combinatorial Aspects of Computational Algebra and Geometry, Combinatorial Optimization, Probabilistic Combinatorics, Combinatorial Aspects of Statistics, and Combinatorics in Mathematical Physics.
Click here for a printable version of the poster.
Directions to the Googleplex can be found here. These directions, however, are for buildings 40-43, not 900 Alta. They therefore require slight modification.
To get to 900 Alta, turn right on Charleston after you get off the highway just as the main directions say, then turn RIGHT on Alta Avenue (not left as you would to get to the main campus). 900 Alta will be on your right. Park in any of the spots in front of the building and proceed to the lobby; there will be signs for BADMath Day.
Carpooling is strongly encouraged. If you need a ride, or if you are able to give rides, please contact your local member of the BADMath Committee.
There is no registration fee, but it is essential that you register with the local organizer, Nick Weininger (n w e i n i n g e r [ a t ] g m a i l . c o m), on or before Wednesday, October 10.
IN THE INTERESTS OF GOOGLE SECURITY, ONLY THOSE WHO HAVE PRE-REGISTERED WILL BE ADMITTED. IF YOU DO NOT PRE-REGISTER YOU WILL NOT BE ALLOWED INTO THE BUILDING AND WILL NOT BE ABLE TO ATTEND. THE DEADLINE TO PRE-REGISTER IS OCTOBER 10TH.
In your registration message, please tell us:
your name and affiliation,
any dietary restrictions you may have, and
whether or not you will be attending dinner afterwards.
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9:00 AM |
Welcome and refreshments |
|
10:00 AM |
Jon McCammond, University of California at Santa Barbara |
|
11:20 AM |
Fumei Lam, Brown University |
|
12:00 PM |
Matt Kahle, Stanford University |
|
12:30 PM |
Break for lunch |
|
2:00 PM |
Ellen Veomett, California State University, East Bay |
|
2:45 PM |
Mauricio Velasco, University of California, Berkeley |
|
3:15 PM |
Coffee break |
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4:00 PM |
Tina Eliassi-Rad, Lawrence Livermore National Laboratory |
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6:00 PM |
Dinner (optional) |
Jon McCammond: Points in the plane and loops in space
The goal of this talk is to highlight some uses of geometric combinatorics in geometric group theory. I will focus on two particular families of finite posets: the more familiar non-crossing partition lattice and the less familiar poset of hypertrees. Combinatorial properties of these posets, such as their moebius functions and the existence of a recursive atom ordering, have strong consequences for cohomological aspects of the two families of infinite groups alluded to in my title. Both are defined as configuration spaces: the more familiar braid groups and the less familiar group of loops. For the most part, the combinatorics will be explicit and the geometric group theory aspects will be treated as a black box, but I will also try to give a rough description of the ways in which the finite combinatorics impacts the intrinsic geometry of these infinite groups.
Fumei Lam: Directed Steiner Arborescences and Constructing Evolutionary Histories
Reconstruction of evolutionary histories is a fundamental problem in computational biology. It has been established that any model that accurately represents the complete evolutionary history must incorporate non-tree operations, corresponding to the mixing of genetic material from ancestral sequences. We will present a model that incorporates these evolutionary processes as well as algorithmic solutions based on a transformation to the Directed Steiner Arborescence Problem and linear programming formulations. This is joint work with Ryan Tarpine and Sorin Istrail.
Matt Kahle: Simple connectivity of random 2-dimensional simplicial complexes
In 1947 Erdos and Renyi studied the threshold for a random graph G(n,p) to be connected. In the past few years, Linial, Meshulam, and Wallach defined a 2-dimensional version of the random graph and exhibited homological analogues of the Erdos-Renyi theorem.
In joint work with Eric Babson and Chris Hoffman, we study the fundamental group of the Linial-Meshulam 2-complexes. We find a threshold that is no longer analogous to the Erdos-Renyi result, but fits in much better with Gromov's picture of random groups. In particular, to put tight bounds on the threshold for simple connectivity involves very general notions of hyperbolicity of a space due to Gromov, which apply just as well to simplicial complexes as to Riemannian manifolds.
As much as possible, the topology and geometry in this talk will be self contained.
Ellen Veomett: Zoology of convex bodies
In this talk, we will study the creatures which are convex bodies, but we will quickly focus on the "dragon" of the lot: the cone of positive semidefinite quadratic forms. We will discuss some uses of this set, including a more recent application in the approximation of convex bodies.
Mauricio Velasco: Some monomial ideals associated to simplicial complexes
The study of the minimal free resolutions of monomial ideals is important for both geometry and combinatorics (via Grobner bases and the Stanley-Reisner correspondence respectively).
There are very few classes of monomial ideals whose minimal free resolutions are explicitly known. In this talk we introduce the class of "Nearly scarf ideals of simplicial complexes" and characterize their minimal free resolutions completely, showing that these ideals are a natural generalization of the Scarf ideals introduced by Bayer,Peeva and Sturmfels.
Nearly Scarf ideals allow us to "turn the problem around" and use topological methods to construct minimal monomial free resolutions with prescribed properties. As an application of this idea we will construct the first example of a minimal monomial free resolution which cannot be supported by a CW-complex.
Tina Eliassi-Rad: Improving Classification Performance in Network Data
In this talk, I will discuss statistical relational learning algorithms that learn and infer values of missing attributes in network data. Specifically, I will present three approaches that improve the classification performance of a relational learner: (1) use of graph-based structural features like betweenness centrality and clustering coefficient; (2) collective classification, where attribute values are collectively inferred; and (3) use of meta-learning algorithms like bagging. These three approaches are complimentary. However, the performance gains associated with graph-based structural features and collective classification depend heavily on the network data having "appropriate" properties. The former relies on the dependence between network structure and class labels, the latter on the dependence between class labels of linked instances. Time permitting, I will outline pitfalls in experimental methodology associated with network data.
Lunch (free) will be provided on-site. There will be a conference dinner at a location to be announced. Everyone is welcome to attend. Both will be vegetarian- and vegan-friendly, but please e-mail Nick (n w e i n i n g e r [ a t ] g m a i l . c o m) with any dietary restrictions you have, especially if they are not satisfied by vegetarian or vegan food. Our chefs will do their best to cater to your particular requirements (which might include acquiring food from a third-party vendor such as a local kosher-compliant kitchen if possible), but they need sufficient notice to make these arrangements. If your dietary restrictions are particularly complicated, we suggest that you begin communicating them to us well in advance of the pre-registration deadline so that our chefs will be completely clear on them by that time.
There will be a conference dinner afterwards at a local restaurant; the exact location is TBD. Typically we organize things so that dinner costs about $15 for students and $25-30 for others.
Nick Weininger, Google (local organizer, contact with any questions at n w e i n i n g e r [ a t ] g m a i l . c o m)
Federico Ardila, San Francisco State University
Ruchira Datta, University of California, Berkeley
Mike Develin, University of California, Berkeley / American Institute of Mathematics
Tim Hsu, San Jose State University
Fu Liu, University of California, Davis
Carol Meyers, Lawrence Livermore National Laboratory
Rick Scott, Santa Clara University