Date: 5 October 2012, 4:30pm
Location: Hempfield High School, Room 213
 Speaker: Mark Johnson, Pennsylvania State University Altoona
   Title: Wheeled Graphs Indexing Operational Structures

Abstract. In joint work with Donald Yau, wheeled graphs are
presented in complete and careful detail, including the fundamental
operation of graph substitution.  The purpose is trying to understand a
wide variety of operational structures, such as operads, PROPs,
properads, dioperads, ... by looking carefully at the graphs used to
index them.  By taking the graph theory seriously, and expanding upon
the vague notion of a pasting scheme suggested by Markl, this allows us
to talk about a wide variety of complicated structures in terms of
fairly elementary properties of graphs.