SOPDEs and Nonlinear Connections
  The canonical k-tangent structure on $T^1_kQ=TQ\oplus\stackrel{k}...\oplus TQ$ allows us to characterize nonlinear connections on $T^1_kQ$ and to develop G\"unther's (k-symplectic) Lagrangian formalism. We study the relationship between nonlinear connections and second-order partial differential equations (SOPDEs), which appear in G\"unther's Lagrangian formalism. 
N. Rom\'an-Roy, M. Salgado, S. Vilari\~no
math-ph math.MP