## Point symmetry groups with invariant nondegenerate planes in the space $$^ 2{\mathbb{R}}_ 4$$.(Russian)Zbl 0669.51016

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
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