The alternating-form symmetric-operator equality conjecture

From papers

Let bb be a non-degenerate alternating bilinear form on an nn-dimensional vector space VV over a field with characteristic not 22. Set

ν:=n2,\nu:=\frac{n}{2},

and let V\mathcal{V} be a nilpotent linear subspace of Sb\mathcal{S}_b with dimension ν(nν)\nu(n-\nu). A maximal partially complete bb-singular flag is denoted by F\mathcal{F}, and NSb,F\mathcal{N}\mathcal{S}_{b,\mathcal{F}} denotes the associated nilpotent subspace.

Alternating-form symmetric-operator equality conjecture. There exists a maximal partially complete bb-singular flag F\mathcal{F} of VV such that

V=NSb,F.\mathcal{V}=\mathcal{N}\mathcal{S}_{b,\mathcal{F}}.

This is one of the two equality cases not covered by the proved results because Sb\mathcal{S}_b is generally not stable under squares when bb is alternating; the conjecture asserts that the corresponding classification still holds.

Progress summary

Open

A paper announced a proof under a large-field condition, but no verified proof has been found and the general problem remains open.

The conjecture says that every largest nilpotent family of operators symmetric for a non-degenerate alternating form has the standard flag-derived form. It is one of the two equality cases left unresolved in the cited treatment.

2018 conditional field-size claim

The paper announces that the remaining conjectures hold when the field is sufficiently large relative to the Witt index, with proofs promised in a subsequent article. The retrieved sources do not identify that article or provide a proof, so this remains an unverified claim rather than a resolution.

Current status (as of August 2026): The conjecture has a conditional, unverified claimed resolution for sufficiently large fields; no verified proof was found here, and the unrestricted case remains open.

Sources
Sources & referencesView supporting material

Primary source

Clément de Seguins Pazzis, “The structured Gerstenhaber problem (I)”, arXiv:1804.07938 (2018).

Solutions 1

Partial progress

The conjecture was solved in the subsequent paper https://arxiv.org/pdf/1806.11355 under a mild cardinality assumption on the underlying field (with characteristic other than 22). The question remains open only for finite fields with odd characteristic and small cardinality with respect to nn.

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