Reduction of Poisson-Nijenhuis Lie algebroids to symplectic-Nijenhuis   Lie algebroids with nondegenerate Nijenhuis tensor
  We show how to reduce, under certain regularities conditions, a Poisson-Nijenhuis Lie algebroid to a symplectic-Nijenhuis Lie algebroid with nondegenerate Nijenhuis tensor. We generalize the work done by Magri and Morosi for the reduction of Poisson-Nijenhuis manifolds. The choice of the more general framework of Lie algebroids is motivated by the geometrical study of some reduced bi-Hamiltonian systems. An explicit example of reduction of a Poisson-Nijenhuis Lie algebroid is also provided. 
Antonio De Nicola, Juan Carlos Marrero, Edith Padron
math.DG math-ph math.MP math.SG