Continuous subgroups of the fundamental groups of physics. II. The similitude group

All subalgebras of the similitude algebra (the algebra of the Poincaré group extended by dilatations) are classified into conjugacy classes under transformations of the similitude group. Use is made of the classification of all subalgebras of the Poincaré algebra, carried out in a previous article. The results are presented in tables listing representatives of each class and their basic properties.