0.2 This ontology covers classes and properties in the theoretical/simulations of physics and astronomy. It includes terms from the IVOA Thesaurus plus terms from the UMD astronomical ontology Ed Shaya, University of Maryland physicalTheory.owl Code in which one follows particles and derivatives are on a per particle basis Determines stability of closed orbits by means of 1st order perturbation analysis. Kolmogorov, Arnold, and Moser Theory. Analysis to find quasi-periodic orbits by splitting potential into regular potentials plus perturbation potential. Code in which derivatives are fixed in space and one is not following the individual particles. Potential Energy. May rotate (hasRotation). hasForce A set of simple potentials that support a finit number of orbit families