Holonomic constraints
In classical mechanics, holonomic constraints are relations between the position variables (and possibly time) which can be expressed in the following form:
, where
are the n coordinates which describe the system. For example, the motion of a particle constrained to lie on the surface of a sphere is subject to a holonomic constraint, but if the particle is able to fall off the sphere under the influence of gravity, the constraint becomes non-holonomic.