In mathematics, an autonomous system is a dynamic equation on a smooth manifold. A non-autonomous system is a dynamic equation on a smooth fiber bundle                     Q        →                  R                         over                               R                        . For instance, this is the case of non-autonomous mechanics.
An r-order differential equation on a fiber bundle                     Q        →                  R                         is represented by a closed subbundle of a jet bundle                               J                      r                          Q                 of                     Q        →                  R                        . A dynamic equation on                     Q        →                  R                         is a differential equation which is algebraically solved for a higher-order derivatives.
In particular, a first-order dynamic equation on a fiber bundle                     Q        →                  R                         is a kernel of the covariant differential of some connection                     Γ                 on                     Q        →                  R                        . Given bundle coordinates                     (        t        ,                  q                      i                          )                 on                     Q                 and the adapted coordinates                     (        t        ,                  q                      i                          ,                  q                      t                                i                          )                 on a first-order jet manifold                               J                      1                          Q                , a first-order dynamic equation reads
                              q                      t                                i                          =        Γ        (        t        ,                  q                      i                          )        .                For instance, this is the case of Hamiltonian non-autonomous mechanics.
A second-order dynamic equation
                              q                      t            t                                i                          =                  ξ                      i                          (        t        ,                  q                      j                          ,                  q                      t                                j                          )                on                     Q        →                  R                         is defined as a holonomic connection                     ξ                 on a jet bundle                               J                      1                          Q        →                  R                        . This equation also is represented by a connection on an affine jet bundle                               J                      1                          Q        →        Q                . Due to the canonical imbedding                               J                      1                          Q        →        T        Q                , it is equivalent to a geodesic equation on the tangent bundle                     T        Q                 of                     Q                . A free motion equation in non-autonomous mechanics exemplifies a second-order non-autonomous dynamic equation.