Oct
30
Planarities and Hanani-Tutte
Speaker Marcus Schaefer DePaul University http://ovid.cs.depaul.edu/ Description The beautiful (and old) Hanani-Tutte theorem states that a graph is planar if and only if it can be drawn so that any...
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- Discrete Applied Math Seminar
Oct
24
Algebraic and Geometric Ideas in Linear Optimization
Speaker Jesus De Loera Department of Mathematics University of California Davis https://www.math.ucdavis.edu/~deloera/ Description Linear programming is undeniably a central software tool of applied...
Oct
16
Location Functions on Trees and Beyond: A Short Survey and Some Recent Results
Description Let G =(V,E) be a finite connected graph and π a k-tuple in V. Think of k customers, each one reporting a most preferred vertex. Location and consensus theory often involves finding the...
Oct
1
Convex Geometries and The Copoint Graph
Description We introduce abstract convex geometries. Much as matroids can be thought of as "discrete vector spaces", convex geometries are "discrete convex hulls". There are specific convex sets of...
Sep
25
Non-Adaptive Group Testing
Description Group testing is a well researched and practically important topic (e.g. in biological research). The basic idea of group testing is to perfectly identify a small portion of 'special'...
Sep
18
Hydra Number of Graphs
Speaker Despina Stasi IIT Applied Math http://www.personal.psu.edu/~users/d/u/dus33/ Description In this talk we define and discuss the hydra number, a graph parameter arising from an optimization...
Sep
13
Graphs with χ = Δ have Big Cliques
Speaker Dan Cranston Virginia Commonwealth University http://www.people.vcu.edu/~dcranston/ Description Let G be a graph with maximum degree Δ ≥3. Brooks' Theorem says that if G has chromatic number Δ...
Sep
4
Introduction to group testing design matrices
Speaker Robert Ellis IIT Applied Math http://math.iit.edu/~rellis/ Description The point of group testing is to reduce the cost of finding defective items in a population by testing pools if items...
May
3
Crossing Number vs. Pairwise Crossing number of graphs
Description The crossing number of a graph $G$, $\crs(G)$ is the minimum number of intersections among edges over all possible drawings on a plane. The pairwise crossing number $\pcr(G)$ is the...
May
2
Counting Independent sets up to tree threshold
Properly colored copies and rainbow copies of large graphs with small maximum degree Description Counting Independent sets up to tree threshold : We consider the problem of counting a given weighted...