In this presentation, I will discuss the hypothesis proposed by Francis and Vavrus (2012) that links rapid Arctic warming (so-called Arctic amplification) to changes in the large-scale atmospheric circulation in the northern hemisphere that favors more persistent weather patterns and a higher likelihood of extreme weather events such as droughts, cold spells, flooding, heavy snows, and heat waves. This hypothesis has been a topic of considerable controversy in recent months, particularly regarding its relationship to the unusual weather conditions that persisted in the winter of 2013/2014. I will discuss various aspects of this linkage, what we know and don't know, and present new related research. Refreshments will be served in CP 173 at 3PM

Title:  Cyclotomic Factors of the Descent Set Polynomial

Abstract:  The descent set polynomial is defined in terms of the descent set statistics of a permutation and was first introduced by Chebikin, Ehrenborg, Pylyavskyy, and Readdy. This polynomial was found to have many factors which are cyclotomic polynomials. In this talk, we will continue to explore why these cyclotomic factors exist, focusing on instances of the 2pth cyclotomic polynomial for a prime p.

Hosted by the Graduate Student Council.  All are welcome to come to mingle over coffee, tea, and cookies.

Title:  Untangling the double twist

Abstract:  The double twist refers to 720 degree rotation of an object around a fixed axis. This loop of rotations can be continuously deformed, through loops, to the trivial, stationary loop. Physical demonstrations of this "untangling" property go by the names of the Dirac Belt Trick, the Dirac String Trick, and the Waiter Trick (also known as the Indonesian Candle Dance). This talk will describe and animate a particularly simple and explicit untangling (originating in work of Francis and Kaufmann). We'll go on to discuss the behavior of arbitrary untanglings of the double twist and their action on vectors in R3. Along the way, we'll meet fundamental groups, quaternions, and projective spaces. This is joint work with David Pengelley.

Title:  Homotopy groups of character varieties

Abstract:  Given a discrete group \Gamma and a (complex reductive or compact) Lie group G, the character variety X_r (G) is the quotient for the conjugation action of G on Hom(\Gamma, G). When G is complex reductive, this quotient should be interpreted in the sense of Geometric Invariant Theory. When G = GL(n) or SL(n), the subspace of irreducible representation coincides with the smooth locus of X_r (G). The rational homology of these spaces has been studied in various cases by a number of authors, and when G = U(n) or SU(n), the homotopy type of the stable moduli spaces X_r (U) and X_r (SU) are explicitly known. In this talk I'll discuss recent progress on understanding low-dimensional homotopy (and integral homology) of character varieties and of their subspaces of irreducible representations. This is joint work with Indranil Biswas, Carlos Florentino, and Sean Lawton.

Title:  Graph Products, Fourier Analysis, and Spectral Techniques

Abstract:  Selected results will be discussed from the paper "Graph Products, Fourier Analysis, and Spectral Techniques" by Noga Alon, Irit Dinur, Ehud Friedgut, and Benny Sudakov.

Title:  Gauss's Golden Theorem (Quadratic reciprocity)

Abstract:  For which odd primes is the congruence $x^2\equiv 0 \mod p$ soluble? The quadratic reciprocity is a marvelous theorem in number theory that deals with this question. We will present examples and a proof of the quadratic residue law (Time permitting).

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This year the University of Kentucky’s Chemistry Department will be having our annual demonstration show to celebrate National Chemistry Week on Friday, October 24^th at 7pm. National Chemistry Week is sponsored by the American Chemical Society and this year is from October 19-October 25^th and the theme is “The Sweet Side of Chemistry: Candy”. We hope to see you at our show!

For visitor parking information, click here.  Please note that the Funkhouser Drive lot is still accessible from Rose Street at this time.

If there are any questions please contact Catherine Denning (cadenning1@uky.edu). 

Faculty Advisor: Dr. Anne-Frances Miller

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This month's guest speaker is Dr. Peter Kekenes-Huskey, who will be presenting a seminar titled Understanding the Chemistry of Heart Function through Computation.

For more information about SACS, click here.

Faculty Sponsor: Dr. Beth Guiton