Magalyas, L. K. Point symmetry groups with invariant nondegenerate planes in the space \(^ 2{\mathbb{R}}_ 4\). (Russian) Zbl 0669.51016 Mat. Issled. 103, 104-121 (1988). Let G be a point symmetry group of the space \(^ 2{\mathbb{R}}_ 4\) which leaves invariant two absolutely perpendicular nondegenerate planes of this space. These planes are of one of the following types: \({\mathbb{R}}_ 2\), \(^ 2{\mathbb{R}}_ 2\), or \(^ 1{\mathbb{R}}_ 2\). Let \(G_ 1\) and \(G_ 2\) be the projections of G upon these planes. Then G can be constructed as a subdirect product of the groups \(G_ 1\) and \(G_ 2\). The purpose of this paper is to investigate all possibilities for such a subdirect product. Reviewer: A.Kontrat’ev MSC: 51M10 Hyperbolic and elliptic geometries (general) and generalizations 20H15 Other geometric groups, including crystallographic groups 51F15 Reflection groups, reflection geometries 20E22 Extensions, wreath products, and other compositions of groups Keywords:point symmetry group; subdirect product PDF BibTeX XML Cite \textit{L. K. Magalyas}, Mat. Issled. 103, 104--121 (1988; Zbl 0669.51016) Full Text: EuDML OpenURL