Power flow, toric deficiency, and strata-confined polyhedral homotopies

Series
Algebra Seminar
Time
Monday, September 8, 2025 - 1:00pm for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Tianran Chen – Auburn University at Montgomery – https://www.tianranchen.org/
Organizer
Donggyu Kim, Julia Lindberg

Please Note: There will be a pre-seminar 10:55-11:15 in Skiles 005.

Power-flow equations model the intricate balancing conditions in electric power grids and are central to analysis and control.  They can be reformulated as Laurent polynomial systems, which makes algebraic and polyhedral techniques applicable.  In this talk, we first explore different ways in which this can be done.

However, certain algebraic formulations may be deficient: the actual number of isolated solutions (counting multiplicity) may fall below the Bernshtein–Kushnirenko–Khovanskii (BKK) bound predicted from Newton polytopes.  By choosing a proper parametrization one uncovers that this deficiency exhibits a certain toric structure.  Recognizing that structure reframes the deficit as a geometric feature rather than a numerical anomaly.  In the second part of this talk, we explore variations of polyhedral homotopy methods designed to respect and exploit this structure.

====(Below is the information on the pre-talk.)====

Title: Mixed volume, mixed cells, and stable self intersections

Abstract: This talk provides an introduction to mixed volume, mixed cells, and their connections to the Bernshtein–Kushnirenko–Khovanskii bound, as well as stable intersections of tropical hypersurfaces.