From teaching experience. I. Symmetry - dissymmetry - antisymmetry

The article is devoted to the discussion of the logical connection of the concepts of symmetry, dissymmetry and antisymmetry in the university course of crystallography. The link between symmetry and dissymmetry is quite obvious, which cannot be said about the link between dissymmetry and antisymmetry. On the example of convex polyhedra, antisymmetry is defined as radical dissymmetry, i. e . translation of all faces of the polyhedron along the normals on the other side of the origin. This methodical technique unites the three concepts and leads to the further development of the theory.