Topology, Geometry and Data Seminar - Daryl DeFord

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Topology, Geometry and Data Seminar
September 26, 2019
2:10PM - 3:10PM
Location
Jennings Hall 355

Date Range
Add to Calendar 2019-09-26 14:10:00 2019-09-26 15:10:00 Topology, Geometry and Data Seminar - Daryl DeFord Title: Hardness results for sampling connected graph partitions with applications to redistricting Speaker: Daryl DeFord, MIT Abstract: The problem of constructing ”fair'' political districts and the related problem of detecting intentional gerrymandering has received a significant amount of attention in recent years. A key problem in this area is determining the expected properties of a representative districting plan as a function of the input geographic and demographic data. A natural approach is to generate a comparison ensemble of plans using MCMC and I will present successful applications of this approach in both court cases and legislative reform efforts. However, our recent work has demonstrated that the commonly used boundary-node flip proposal can mix poorly on real-world examples. In this talk, I will present some new proposal distributions for this setting and discuss some related open problems concerning mixing times and spanning trees. I will also discuss some generic hardness results for sampling problems on partitions of planar graphs.  Seminar URL: https://tgda.osu.edu Jennings Hall 355 Department of Mathematics math@osu.edu America/New_York public
Description

Title: Hardness results for sampling connected graph partitions with applications to redistricting

Speaker: Daryl DeFord, MIT

Abstract: The problem of constructing ”fair'' political districts and the related problem of detecting intentional gerrymandering has received a significant amount of attention in recent years. A key problem in this area is determining the expected properties of a representative districting plan as a function of the input geographic and demographic data. A natural approach is to generate a comparison ensemble of plans using MCMC and I will present successful applications of this approach in both court cases and legislative reform efforts. However, our recent work has demonstrated that the commonly used boundary-node flip proposal can mix poorly on real-world examples. In this talk, I will present some new proposal distributions for this setting and discuss some related open problems concerning mixing times and spanning trees. I will also discuss some generic hardness results for sampling problems on partitions of planar graphs. 

Seminar URL: https://tgda.osu.edu

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