Min-plus dot products and greedy multiplication of permutations
COLLOQUIUMS: OTHER COLLOQUIUMS, COLLOQUIUMS
When: February 10, 2025
4:00 pm - 5:15 pm
Where: Science Center 507
Address:
1 Oxford Street, Cambridge, MA 02138, United States
Speaker: Nathan Pflueger - Amherst College
The usual multiplication rule for integer permutations is given by function composition. However, permutations also possess an intriguing associative operation called the Demazure or 0-Hecke product, characterized by a greedy algorithm. I keep encountering this product quite accidentally while doing geometry. I will describe some of these encounters with the Demazure product, which stem from a surprising alternative description of it in terms of dot products in the min-plus (or tropical) semiring.
There will be a reception in the Math Common Room, Science Center, 4th Floor, immediately following the talk.