Rigidity of integral coisotropic submanifolds of contact manifolds

Unlike Legendrian submanifolds, the deformation problem of coisotropic submanifolds can be obstructed. Starting from this observation, the special class of integral coisotropic submanifolds is singled out as the direct analogue of Legendrian submanifolds for what concerns deformation theory. Indeed, being integral coisotropic is a rigid condition, so that the integral coisotropic deformation problem is unobstructed.