Robert Gray’s paper on Lie point symmetries appears in PRSLA

generatorsThe paper “The Lie point symmetry generators admitted by systems of linear differential equations“, by Robert Gray, which formed part of his PhD thesis, has been published in the Proceedings A of the Royal Society of London. Computing the Lie point symmetries of systems of linear differential equations can be prohibitively difficult. For homogeneous systems in Kovalevskaya form of order two or higher, this paper proves the existence of a basis of infinitesimal generators (as determined by Lie’s algorithm) whose characteristic forms are homogeneous in the dependent variables of degree zero, one or two.  The electronic version of the paper can be downloaded here.