A SINGULAR POINCARE LEMMA EVA MIRANDA AND VU NGOC SAN Prepublication de l'Institut Fourier no 664 (2005) Abstract. We prove a Poincare lemma for a set of r smooth functions on a 2n-dimensional smooth manifold satisfying a commutation relation determined by r singular vector fields associated to a Cartan subalgebra of sp(2r, R). This result has a natural interpretation in terms of the cohomology associated to the infinitesimal deformation of a completely integrable system. 1. Introduction The classical Poincare lemma asserts that a closed 1-form on a smooth manifold is locally exact. In other words, given m-functions gi on an m- dimensional manifold for which ∂∂xi (gj) = ∂ ∂xj (gi) there exists a smooth F in a neighbourhood of each point such that gi = ∂∂xi (F ). Now assume that we have a set of r functions gi and a set of r vector fields Xi with a singularity at a point p and fulfilling a commutation relation of type Xi(gj) = Xj(gi). We want to know if a similar expression for gi exists in a neighbourhood of p. In the case gi are n functions on the symplectic manifold (R2n, ∑ i dxi ? dyi) and Xi form a basis of a Cartan subalgebra of sp(2n, R) a Poincare- like lemma exists.
- hamiltonian vector
- consider singular
- dxi?dyi then
- poincare lemma
- singular poincare
- vector fields
- poincare- like lemma
- lemma
- functions