Seminar Calendar
for events the day of Tuesday, March 29, 2011.

.
events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
    February 2011            March 2011             April 2011
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4  5          1  2  3  4  5                   1  2
6  7  8  9 10 11 12    6  7  8  9 10 11 12    3  4  5  6  7  8  9
13 14 15 16 17 18 19   13 14 15 16 17 18 19   10 11 12 13 14 15 16
20 21 22 23 24 25 26   20 21 22 23 24 25 26   17 18 19 20 21 22 23
27 28                  27 28 29 30 31         24 25 26 27 28 29 30



Tuesday, March 29, 2011

Topology Seminar
11:00 am   in 241 Altgeld Hall,  Tuesday, March 29, 2011
 Del Edit Copy
Submitted by mando.
 Ralph Kaufmann (Purdue)BV operator, G-bracket, master equation and all thatAbstract: Building on the classical results of Gerstenhaber, we show in what similar situations one naturally obtains an odd Lie/Poisson aka. Gerstenhaber bracket. In the same vein we discuss in what standard examples BV operators appear and are natural. These examples are at the chain/homology level as well as at the topological level as they appear in string topology and Zwiebach's string field theory formalism. Finally, we discuss a new monoidal categorical version of generalizing operads in which the classical and new examples are special cases of a general structure.

Harmonic Analysis and Differential Equations
1:00 pm   in 347 Altgeld Hall,  Tuesday, March 29, 2011
 Del Edit Copy
Submitted by ekirr.
 Nabile Boussaid (Universite Franche-Comte, Besancon, France)On stability of standing waves of nonlinear Dirac equationsAbstract: This is a joint work with Scipio Cuccagna (University of Trieste). We consider the stability problem for standing waves of nonlinear Dirac models. Under a suitable definition of linear stability, and under some restriction on the spectrum, we prove at the same time orbital and asymptotic stability. There are more spectral restrictions than in the case of the nonlinear Schrödinger equation, because of the strong indefiniteness of the energy.

Logic seminar
1:00 pm   in 345 Altgeld Hall,  Tuesday, March 29, 2011
 Del Edit Copy
Submitted by vddries.
 Larry Moss (Indiana University)Natural LogicAbstract: A central motivation for modern logic is that it provides a tool to represent natural language meaning and inference.  One of the motivations of first-order logic is precisely that one can translate significant aspects of language into it, and in addition one can use it in connection with the foundations of mathematics.   This talk returns to the topic  of language and logic, and proposes new logical systems for the area. One leading idea is to propose logics with a decidable validity problem, ruling out full first-order logic.  Indeed, we are interested in finding decidable fragments of language, just as others have asked for decidable fragments of first-order logic. We also axiomatize the logics, just to see what they look like. The  overall topic of this research could be interesting to those pursuing natural language semantics and also to people in computational linguistics who work on inference.    It also could be of interest to historians of logic, since in effect, we are asking what traditional logic would have evolved into if it had the mathematical tools that are so prominent in modern logic.    The talk mentions a number of technical results, and they are closest to algebraic logic, model theory and descriptive complexity theory.

Probability Seminar
2:00 pm   in 347 Altgeld Hall,  Tuesday, March 29, 2011
 Del Edit Copy
Submitted by rsong.
 Prof. Janos Englander (University of Colorado)Particle models with interaction via the center of massAbstract: Recently a number of particle models have been studied where individuals move in space and also interact via the center of the system (given by the center of mass). I will review some of my results as well as those of Gill, Balazs and Racz.

Graph Theory and Combinatorics
3:00 pm   in 241 Altgeld Hall,  Tuesday, March 29, 2011
 Del Edit Copy
Submitted by west.
 Russ Woodroofe (Washington University, St. Louis)Chordal clutters and k-decomposabilityAbstract: I'll present a family of clutters (antichains of sets) that generalize both various antichains formed from chordal graphs and the circuit antichains of matroids. My interest in these arose from the "shellability" condition in geometric combinatorics. I'll give background on shellability and on some easier properties (k-decomposability) implying shellability. There are nice combinatorial consequences, including computability of independence numbers of graphs in some new situations. Other, non-geometric properties of chordal graphs and/or matroid circuits may also extend to this family.

Ergodic Theory
4:00 pm   in 347 Altgeld Hall,  Tuesday, March 29, 2011
 Del Edit Copy
Submitted by jathreya.
 Caleb Eckhardt (Purdue)Markov operators and topological entropyAbstract: We'll discuss the topological entropy of some Markov operators associated with certain transformations of the unit interval.