Alexander O. Foster | Searcharxiv

arXiv2025

Tangent Weights and Invariant Curves in Type A Bow Varieties

This paper provides a complete classification of torus-invariant curves in Cherkis bow varieties of type A. We develop combinatorial codes for compact and noncompact invariant curves involving the butterfly diagrams, Young diagrams, and binary contingency tables. As a key intermediate step, we also develop a novel tangent weight formula. Finally, we apply this new machinery to example bow varieties to demonstrate how to obtain their 1-skeletons (union of fixed points and invariant curves).

math.AG↗

arXiv2024

Geometric Bruhat order on (0,1)-matrices

The combinatorially and the geometrically defined partial orders on the set of permutations coincide. We extend this result to $(0,1)$-matrices with fixed row and column sums. Namely, the Bruhat order induced by the geometry of a Cherkis bow variety of type A coincides with one of the two combinatorially defined Bruhat orders on the same set.

math.CO↗