Total Positivity, graphs, tilings and Weakly separated sets

Series
Combinatorics Seminar
Time
Friday, December 9, 2011 - 3:05pm for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
SuHo Oh – University of Michigan, Ann Arbor – suho@math.mit.edu
Organizer
Prasad Tetali
Wiring diagrams are classical objects of combinatorics. Plabic graphs were defined by Postnikov, to study the total positivity of the Grassmannian. We will show how to generalize several definitions and properties of wiring diagrams to Plabic graphs, proving a conjecture by Leclerc-Zelevinsky and Scott on the way. We will begin with a brief introduction to total positivity and end with connection to cluster algebras. Major part of the talk comes from a joint work with Alexander Postnikov and David Speyer.