anisotropy, ideal plasticity, affine modeling, quasi-incompressible, flat deformation.

The anisotropic environments, submitting to square-law criterion of plasticity are considered. Construction of the theory of ideal plasticity of anisotropic environments by means of use of affine modeling is offered. Affine transformations of coordinates, a component of a vector of speed of moving, a component of tensors stress and speeds of deformation are entered. The hypothesis about incompressible plastic current in affine space (a hypothesis about quasiincompressible) is accepted. This hypothesis imposes only one restriction on factors of a plastic pliability. For the environment with monoclinic symmetry the equations of flat deformation are resulted. It is shown, that the equations of a field of pressure and speeds of movings are hyperbolic. Characteristics of these fields in affine space coincide.