Modules determined by their Newton polytopes
Peigen Cao
TL;DR
The paper introduces Newton polytopes $\mathcal{N}(U)$ of quotient-dimension vectors to distinguish modules beyond their dimension vectors, and proves that for finite-dimensional basic algebras, sharing a Newton polytope forces equivalence in the associated torsion- and mutation-theoretic data. The main theorem shows that indecomposable $\tau$-rigid modules and left finite bricks are uniquely determined by their Newton polytopes, and that $U\oplus V$ is $\tau$-rigid when $U,V$ are $\tau$-rigid. A corollary for $\tau$-tilting finite algebras asserts bricks are uniquely determined by Newton polytopes, highlighting the power of polyhedral invariants to classify modules beyond dimension vectors.
Abstract
In the $τ$-tilting theory, there exist two classes of foundamental modules: indecomposable $τ$-rigid modules and left finite bricks. In this paper, we prove the indecomposable $τ$-rigid modules and the left finite bricks are uniquely determined by their Newton polytopes spanned by the dimensional vectors of their quotient modules. This is a kind of generalization of Gabriel's result that the indecomposable modules over path algebras of Dynkin quivers are uniquely determined by their dimensional vectors.
