@misc{StephaniWolf, author = {Stephani, Hans and Wolf, Thomas}, title = {Spherically symmetric perfect fluids in shearfree motion - the symmetry approach}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-2253}, number = {SC-96-14}, abstract = {In General Relativity, the motion of expanding shearfree perfect fluids is governed by the ordinary differential equation \$y^{\prime \prime }=\$ \$\% F(x)\,y^2\$ , where \$F\$ is an arbitrary function from which the equation of state can be computed. A complete symmetry analysis of this differential equation is given; its solutions are classified according to this scheme, and in particular the relation to Wyman's Painlev\'e analysis is clarified.}, language = {en} }