4 papers
Enumeration of Nondegenerate Hypermatrices
Brandon Koprowski, Joel Brewster Lewis
We consider the problem of enumerating hypermatrices of format over a finite field that have nonzero hyperdeterminant and whose nonzero entries are rest…
Upho lattices II: ways of realizing a core
Sam Hopkins, Joel B. Lewis
A poset is called upper homogeneous, or "upho," if all of its principal order filters are isomorphic to the whole poset. In previous work of the first author, it was shown that eac…
Interval-closed set rowmotion and homomesy on products of two chains
Nadia Lafrenière, Joel Brewster Lewis, Erin McNicholas +2
We study rowmotion dynamics on interval-closed sets. Our first main result proves a simplification of the global definition of interval-closed set rowmotion from (Elder, Lafrenièr…
Global patterns in signed permutations
Owen John Levens, Joel Brewster Lewis, Bridget Eileen Tenner
Global permutation patterns have recently been shown to characterize important properties of a Coxeter group. Here we study global patterns in the context of signed permutations, w…