A Darboux classification of homogeneous Pfaffian forms on graded manifolds

TL;DR

This paper extends Darboux's classical classification to homogeneous Pfaffian forms on graded supermanifolds, providing homogeneous Darboux coordinates and normal forms under regularity conditions.

Contribution

It introduces a supergeometric Darboux classification for homogeneous Pfaffian forms, generalizing classical theorems to graded manifolds with homogeneity structures.

Findings

Homogeneous Darboux coordinates exist for forms of given degree.

Characteristic distribution controls local equivalence of forms.

Results apply to both supermanifolds and ordinary manifolds.

Abstract

We study the local classification problem for differential Pfaffian forms on a supermanifold $M$ that are homogeneous with respect to a given homogeneity structure on $M$. The best-known homogeneity structures are those associated with linearity on a vector bundle. The aim is to show that, for a homogeneous form of given degree, there are `Darboux coordinates' which are homogeneous. As a consequence, we obtain Darboux-type normal pictures for homogeneous forms, recovering the classical Darboux theorems, as well as their contact and presymplectic counterparts as special cases. To obtain an analog of Darboux's classification in the supergeometric context, we define a class of a differential form $\alpha$ by the rank of the characteristic distribution $\chi(\alpha)$, being the intersection of kernels of $\alpha$ and $d\alpha$. We show that, under suitable regularity and constant-rank assumptions, this distribution completely controls the local equivalence problem for homogeneous Pfaffian forms. Our results hold as well for ordinary (purely even) manifolds.