# Mathematics Colloquium Calendar

### Upcoming Mathematics Colloquia

On Friday, December 8,, Krener Assistant Professor of Mathematics at the University of California at Davis, will present a colloquium on Site-specific recombination on circular DNA molecules and band surgery along the trefoil knot. The talk will take place at 1:00 pm, in Room 205 of

Abstract: A typical bacterial chromosome, for example the chromosome of the Escherichia coli organism, is a single, circular DNA molecule. During packing, reconnection events and other cellular processes, knots and links can form in DNA, and left unresolved, these knots and links can be problematic for the health of the cell. For example, during replication, two interlinked daughter chromosomes are produced. The cell employs a host of enzymes which correct topological linking via strand-passage or site-specific recombination, ensuring the survival of the cell. Circular DNA is modeled as a topological knot or link, and the most relevant links in this context are the $$T(2, n)$$ torus knots and links, the most common of which is the right-handed trefoil $$T(2, 3)$$. Local reconnection events on circular DNA, in particular, site-specific recombination at sites in direct repeat or inverted repeat, are modeled topologically by band surgery operations on knots and links. Within this knot theoretic framework, we will classify all band surgery operations from the trefoil knot to the $$T(2, n)$$ torus knots and links. This result is obtained from a related classification result that we prove in three-manifold topology, namely a version of the lens space realization problem. In particular, we will classify certain Dehn surgeries on knots in the lens space $$L(3, 1)$$, a result which is proved by studying the behavior of the Heegaard Floer d-invariants under integral surgery along knots in $$L(3,1)$$. This project is joint work with Lidman and Vazquez.

### Recent Mathematics Colloquium Talks

Date Topic Speaker
Dec 1, 2017 Promoting rough draft thinking to engage students in mathematics classroom discourse Dr. Amanda Jansen,
University of Delaware
Nov 10, 2017 Numerical algorithms of some multiphysics problems in incompressible fluid dynamics  Dr. Mingchao Cai
Morgan State University
Oct 27, 2017 An agile approach to data assimilation  Dr. Peter Horn,
MITRE Corp.
Oct 6, 2017 Rook and Wilf equivalence of integer partitions  Dr. Jonathan Bloom
Lafayette College
Sept 21, 2017 Counting integer points in polytopes with an extension of Presburger arithmetic  Dr. John Goodrick,
Los Andes University
Sept 14, 2017 Constructing nonstandard finite difference (NSFD) schemes for dynamical systems Seye Adekanye,
Howard University
Apr 27, 2017 Prediction methods for semi-continuous data with applications in climate science Dr. Nagaraj K. Neerchal, UMBC
Apr 18, 2017 Lyapunov rank in conic optimization Dr. Michael Orlitzky,
UMBC
Apr 7, 2017 Managing default risk in affordable housing finance Dr. Tyler T. Yang,
IFE Group
Mar 9, 2017 Covariates-contributed sufficient dimension reduction Dr. Kofi Placid Adragni, UMBC
Nov 10, 2016 Dimensions of spline spaces and commutative algebra Dr. Michael DiPasquale,
Oklahoma State University
Oct 13, 2016 A lattice theorist's apology Dr. Jonathan Farley,
Morgan State University
Oct 6, 2016 The idea of dimension in model theory and discrete mathematics Dr. Cameron D. Hill, Wesleyan University
Sept 22, 2016 Jonathan Farley's mathematical terror theory: The structure of perfect terrorist cells with a single leader Ms. Zeinab Bandpey,
Morgan State University