#### Contact Info

Combinatorics & Optimization

University of Waterloo

Waterloo, Ontario

Canada N2L 3G1

Phone: 519-888-4567, ext 33038

PDF files require Adobe Acrobat Reader.

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Friday, November 22, 2013 — 3:30 PM to 4:30 PM EST

Speaker: | Andrew Childs |
---|---|

Affiliation: | University of Waterloo |

Room: | Mathematics and Computer Building (MC) 5158 |

Many problems in combinatorics, statistical mechanics, number theory and analysis give rise to power series (whether formal or convergent) of the form $$ f(x,y) \;=\; \sum\limits_{n=0}^\infty a_n(y) \, x^n \;, $$ where $\{a_n(y)\}$ are formal power series or analytic functions satisfying $a_n(0) \neq 0$ for $n=0,1$ and $a_n(0) = 0$ for $n \ge 2$. Furthermore, an important role is played in some of these problems by the roots $x_k(y)$ of $f(x,y)$ --- especially the "leading root'' $x_0(y)$, i.e.\ the root that is of order $y^0$ when $y \to 0$. Among the interesting series $f(x,y)$ of this type are the "partial theta function'' $$ \Theta_0(x,y) \;=\; \sum\limits_{n=0}^\infty x^n \, y^{n(n-1)/2} \;, $$ which arises in the theory of $q$-series, and the ``deformed exponential function'' $$ F(x,y) \;=\; \sum\limits_{n=0}^\infty {x^n \over n!} \, y^{n(n-1)/2} \;, $$ which arises in the enumeration of connected graphs. These two functions can also be embedded in natural hypergeometric and $q$-hypergeometric families.

In this talk I will describe recent (and mostly unpublished) work concerning these problems --- work that lies on the boundary between analysis, combinatorics and probability. In addition to explaining my (very few) theorems, I will also describe some amazing conjectures that I have verified numerically to high order but have not yet succeeded in proving. My hope is that one of you will succeed where I have not!

Location

MC - Mathematics & Computer Building

5158

200 University Avenue West

Waterloo, ON N2L 3G1

Canada

200 University Avenue West

Waterloo, ON N2L 3G1

Canada

Combinatorics & Optimization

University of Waterloo

Waterloo, Ontario

Canada N2L 3G1

Phone: 519-888-4567, ext 33038

PDF files require Adobe Acrobat Reader.

University of Waterloo

University of Waterloo

43.471468

-80.544205

200 University Avenue West

Waterloo,
ON,
Canada
N2L 3G1

The University of Waterloo acknowledges that much of our work takes place on the traditional territory of the Neutral, Anishinaabeg and Haudenosaunee peoples. Our main campus is situated on the Haldimand Tract, the land granted to the Six Nations that includes six miles on each side of the Grand River. Our active work toward reconciliation takes place across our campuses through research, learning, teaching, and community building, and is centralized within our Indigenous Initiatives Office.