Candice Price, Department of Mathematics, University of Iowa Title: Tangle Model Workshop Abstract: The tangle model was developed in the 1980's by professors DeWitt Sumner and Claus Ernst. This model uses the mathematics of tangles to model protein-DNA binding. An n-string tangle is a pair (B,t) where B is a 3-dimensional ball and t is a collection of n non-intersecting curves properly embedded in B. n- string tangles are formed by placing 2n points on the boundary of B, denoted ∂B, and attaching n non-intersecting curves inside B. Tangles, like knots and links, are studied through their diagrams. In the tangle model for DNA site-specific recombination, one is required to solve simultaneous equations for unknown tangles which are summands of observed DNA knots and links. This workshop will give a review of the tangle model for site specific recombination, including definitions and an example. We will also work with an KnotPlot app called "TopoIce".