Quotient–submodule equidistribution conjecture

For every finite-dimensional representation-finite algebra AA and every integer i≥0i\ge 0, the number of quotient-closed full additive subcategories C⊆mod⁡A\mathcal{C}\subseteq \operatorname{mod}A satisfying ∣ind⁡(C)∣=i|\operatorname{ind}(\mathcal{C})|=i equals the number of submodule-closed full additive subcategories D⊆mod⁡A\mathcal{D}\subseteq \operatorname{mod}A satisfying ∣ind⁡(D)∣=i|\operatorname{ind}(\mathcal{D})|=i. Here quotient-closed means closed under factor modules, submodule-closed means closed under submodules, and ∣ind⁡(C)∣|\operatorname{ind}(\mathcal{C})| denotes the number of isomorphism classes of indecomposable modules in C\mathcal{C}, with analogous notation for D\mathcal{D}.

References

Progress summary

Refreshed
Claimed progress

Several important special cases are now proved, but the full conjecture remains open.

The conjecture predicts an equidistribution phenomenon connecting categorical enumeration with Bruhat intervals and convex-geometric structure. Its general representation-finite case is not settled.

August 2026 special-case results

The conjecture is proved for extreme sizes, Nakayama algebras, radical-square-zero algebras, and representation-directed algebras. The general representation-finite case remains open.

Current status (as of August 2026): Several substantial algebra classes and extreme-size cases are settled, while the general representation-finite case remains open.

Sources

Solutions 0

No solutions have been posted yet.