English

Projective geometry from Poisson algebras

Metric Geometry 2010-12-10 v2

Abstract

In analogy with the Poisson algebra of the quadratic forms on the symplectic plane, and the notion of duality in the projective plane introduced by Arnold in \cite{Arn}, where the concurrence of the triangle altitudes is deduced from the Jacobi identity, we consider the Poisson algebras of the first degree harmonics on the sphere, the pseudo-sphere and on the hyperboloid, to obtain analogous duality notions and similar results for the spherical, pseudo-spherical and hyperbolic geometry. Such algebras, including the algebra of quadratic forms, are isomorphic, as Lie algebras, either to the Lie algebra of the vectors in R3\R^3, with vector product, or to algebra sl2(R)sl_2(\R). The Tomihisa identity, introduced in \cite{Tom} for the algebra of quadratic forms, holds for all these Poisson algebras and has a geometrical interpretation. The relation between the different definitions of duality in projective geometry inherited by these structures is shown.

Keywords

Cite

@article{arxiv.0912.1495,
  title  = {Projective geometry from Poisson algebras},
  author = {Francesca Aicardi},
  journal= {arXiv preprint arXiv:0912.1495},
  year   = {2010}
}

Comments

18 pages, 9 figures

R2 v1 2026-06-21T14:21:06.274Z