The paper is devoted to the complete classification of all real Lie algebras of contact
vector fields on the first jet space of one-dimensional submanifolds in the plane. This
completes Sophus Lie’s classification of all possible Lie algebras of contact
symmetries for ordinary differential equations. As a main tool we use the abstract
theory of filtered and graded Lie algebras. We also describe all differential and
integral invariants of new Lie algebras found in the paper and discuss the
infinite-dimensional case.
Received: 19 May 1998
Revised: 27 November 1998
Accepted: 16 February 1999
Published: 15 March 1999
Proposed: Frances Kirwan
Seconded: Simon Donaldson, Robion Kirby