In Lagrangian mechanics, a different set of coordinates are used, called the generalized coordinates. These are commonly denoted as ( q i , q ˙ i ) {\displaystyle \left(q^{i},{\dot {q}}^{i}\right)} with q i {\displaystyle q^{i}} called the generalized position and q ˙ i {\displaystyle {\dot {q}}^{i}} the generalized velocity. When a Hamiltonian is defined on the cotangent bundle, then the generalized coordinates are related to the canonical coordinates by means of the Hamilton–Jacobi equations.