On noether symmetries and conservation laws.

摘要

Noether symmetries provide conservation laws that are admitted by Lagrangians representing physical systems. For differential equations possessing Lagrangians these symmetries are obtained by the invariance of the corresponding action integral. In this thesis we find Noether symmetries and conserved vectors for a Lagrangian constructed from a metric that represents Milne model and is of interest in general relativity. For completeness, we construct wave equation on this metric, obtain its Lie symmetries and compare them with spacetime isometries.