Department of Mathematics
Mathematics Colloquium
Organizer Mailing list: https://groups.google.com/forum/#!forum/ccnymathcolloquium/joinThe Mathematics Department Colloquium typically meets on Thursdays from 12:30 pm to 1:20 pm in NAC 6/114. This will typically be preceded by tea and coffee at noon in the math lounge, and will be followed by lunch. To receive announcements via email, please join our google group
Upcoming talks

Thursday, March 21, 2019, 12:30PM, NAC 6/114
Yung Choi (U. Conn), TBATBA

Thursday, March 28, 2019, 12:30PM, NAC 6/114
Konstantin Mischaikow (Rutgers U.), A combinatorial/algebraic topological approach to nonlinear dynamicsMotivated by the increase in data driven science I will discuss a combinatorial/algebraic topological approach to characterizing nonlinear dynamics. In particular, I will describe how order theory can be used to efficiently and effectively organize the decomposition of dynamics and how algebraic topological tools can be used to characterize the structure of the dynamics. I will then propose a definition of nonlinear dynamics based on these structures. To demonstrate the effectiveness of this approach I will consider several problems from systems and synthetic biology. I will focus on identification and rejection of network models for these types of systems based on functional form and time series data.

Thursday, May 09, 2019, 12:30PM, NAC 6/114
Linda Keen (Lehman College (CUNY)), TBATBA
Most recent talks

Thursday, February 21, 2019, 12:30PM, NAC 6/114
Vincent Martinez (Hunter College (CUNY)), Studies in analyticity for hydrodynamic and chemotaxis modelsIn their 1987 seminal paper, Foias and Temam established analyticity in both space and time for solutions of the two(2D) and threedimensional (3D) NavierStokes equations (NSE) by developing an energy method now known as the technique of Gevreynorms, i.e., a norm which characterizes real analyticity of a function. This approach has since become standard for establishing spatial analyticity of solutions to various parabolictype equations. In this talk, we shed light on the relation between the structure of the equation and its wellposedness theory in various analytic Gevreynorm regularity classes. We do so in the context of the supercritical SQG equation, the KellerSegel equation, and a coupled chemotaxishydrodynamic model through the notion of “criticality.”

Thursday, February 07, 2019, 12:30PM, NAC 6/114
Ethan Akin (CCNY), On Nontransitive DiceThere exist nonstandard intransitive 6sided dice. A nonstandard die is labeled with positive numbers and repeats are allowed. A die A beats die B if Prob(A > B) > 1/2. There exist such dice with A beats B, B beats C and C beats A. We show that with n Ksided dice (large K) any tournament can be modeled. A tournament on n is a choice of direction i beats j or j beats i for any pair i,j of distinct numbers between 1 and n. The talk should be accessible to undergrads.

Thursday, December 06, 2018, 12:30PM, NAC 6/114
Giulio Tiozzo (University of Toronto), Trees, entropy, and the Mandelbrot setThe notion of topological entropy, arising from information theory, is a fundamental tool to understand the complexity of a dynamical system. When the dynamical system varies in a family, the natural question arises of how the entropy changes with the parameter.
In the last decade, W. Thurston introduced these ideas in the context of complex dynamics by defining the "core entropy" of a quadratic polynomials as the entropy of a certain forwardinvariant set of the Julia set (the Hubbard tree).
As we shall see, the core entropy is a purely topological / combinatorial quantity which nonetheless captures the richness of the fractal structure of the Mandelbrot set. In particular, we will relate the variation of such a function to the geometry of the Mandelbrot set. We will also prove that the core entropy on the space of polynomials of a given degree varies continuously, answering a question of Thurston.