Equations of motion when masses move according to Newton's law of gravity. In general relativity, rotational motion is described by the relativistic angular momentum tensor, including the spin tensor, which enter the equations of motion under covariant derivatives with respect to proper time. The Mathisson–Papapetrou–Dixon equations describe the motion of spinning objects moving in a gravitational field. Unlike the equations of motion for describing particle mechanics, which are systems of coupled ordinary differential equations, the analogous equations governing the dynamics of waves and fields are always partial differential equations, since the waves or fields are functions of space and time. For a particular
Valerio-Horatian Laws on the plebiscites, there were three instances of such law. There were two other laws on appeal which were proposed by two consuls who were also members of the Valeria family, one by Publius Valerius Publicola in 509 BC and one by Marcus Valerius Corvus in 300 BC. Two other laws which provided for the plebiscites to be binding on the whole people were also proposed, one by Quintus Publilius Philo in 339 BC and one by Quintus Hortensius in 287 BC. This has led some historians to argue that in both cases the first and second laws are unhistorical