Motivated from his p-adic study of the variation of the zeta function as
the variety moves through a family, Dwork conjectured that a new type of
L-function, the so-called unit root L-function, was always p-adic
meromorphic. In the late 1990s, Wan proved this using the theory of
sigma-modules, demonstrating that unit root L-functions have structure.
Little more is known.
This talk is concerned with unit root L-functions coming from families of
exponential sums. In this case, we demonstrate that Wan's theory may be
used to extend Dwork's theory -- including p-adic cohomology -- to these
L-functions. To illustrate the technique, the unit root L-function of the
Kloosterman family is studied in depth.
Bernstein and Breiner found a characterization of the catenoid that the area of a minimal annulus in a slab is bigger than that of the maximally stable catenoid. We give a simpler proof of their theorem and extend the theorem to some minimal surfaces with genus (joint work with Benoit Daniel). New characterizations of the helicoid recently proved by Eunjoo Lee will be also presented.
University of California, Irvine, Department of Mathematics
Time:
Tuesday, March 3, 2015 - 10:00am
Location:
340N Rowland Hall
The purpose of this thesis is to use the tools of Inner Model Theory to the study of notions relative to generic embeddings induced by ideals. We seek to apply the Core Model Induction technique to obtain lower bounds in consistency strength for a specific stationary catching principle called StatCatch*(I), related to the saturation of an ideal I of omega_2. This principle involves the central notion of self-genericity in its formulation, introduced by Foreman, Magidor and Shelah. In particular, we show that assuming StatCatch*(I) (plus some additional hypothesis in the universe), we can obtain, for every finite n, an inner model with n Woodin Cardinals.
An arc in the projective plane over a finite field Fq is a collection of points, no three of which lie on a line. Segre’s theorem tells us that the largest size of an arc is q+1 when q is odd and q+2 when q in even. Moreover, it classifies these maximal arcs when q is odd, stating that every such arc is the set of rational points of a smooth conic.
We will give an overview of problems about arcs in the plane and in higher dimensional projective spaces. Our goal will be to use algebraic techniques to try to understand these extremal combinatorial configurations. We will also see connections to special families of error-correcting codes and to modular forms.
We will explain a systematic way to study a type of curve flows in R^{n+1, n}, whose geometric invariants are solutions of some integrable systems. In detail, we will construct a hierarchy of isotropic curve flows in R^{2, 1}, construct explicit solutions from Backlund transformation, and study its Hamiltonian formulation.
The Keller-Segel equations model chemotaxis of bio-organisms. In a reduced form, considered in this talk, they are related to Vlasov equation for self-gravitating systems and are used in social sciences in description of crime patterns.
It is relatively easy to show that in the critical dimension 2 and for mass of the initial condition greater than 8 \pi, the solutions 'blowup' (or 'collapse') in finite time. This blowup is supposed to describe the chemotactic aggregation of the organisms and understanding its mechanism, especially its universal features, would allow to compare theoretical results with experimental observations. Understanding this mechanism turned out to be a very subtle problem defying solution for a long time.
In this talk I discuss recent results on dynamics of solutions of the (reduced) Keller-Segel equations in the critical dimension 2 which include a formal derivation and partial rigorous results on the blowup dynamics of solutions. The talk is based on the joint work with S. I. Dejak, D. Egli and P.M. Lushnikov.
We study the monodromy of a certain class of semistable hyperelliptic curves over the rationals that was introduced by Shigefumi Mori forty years ago (before his Minimal Model Program). Using ideas of Chris Hall, we prove that the corresponding $\ell$-adic monodromy groups are (almost) ``as large as possible". We also discuss an explicit construction of two-dimensional families of hyperelliptic curves over an arbitrary global field with big monodromy.
The importance of price impact in HFT is outlined via well known phenomena of micro-price. We look at price impact as macro phenomena and for its explanation turn to micro phenomena, specifically to order book dynamics modeled via multi-dimensional Hawkes processes. We then show that on the level of first-moment simplification of the model that this type of order book implies well known phenomena of price impact observed by Almgren and more precise one proposed by Gatheral.
We use stationary processes and ergodic theory to study high frequency trading and technical analysis. Our discussion is based on data from Chinese markets.