Debra Boutin, the Samuel F Pratt Professor of Mathematics Emerita, gave an invited presentation titled "Geochromatic Number in terms of Chromatic Number" in the Graph Colouring and Homomorphism Minisymposium at the Society of Industrial and Applied Mathematics Discrete Math Conference in Spokane, Wash.
In her talk, Boutin described an extension of the idea of graph homomorphism, an extensively studied topic in graph theory, to graphs given with a specific drawing in the Euclidean plane. In particular, she showed how, in some situations, the size of the smallest graphs to which a graph is homomorphic is related when a specific drawing is given and when it is not.
