We introduce a notion of the Kirichenko space which is connected with the notion of Gorenstein matrix (see [2], ch. 14). Every element of Kirichenko space is an n × n matrix, whose elements are solutions of the equations ...

The variety J orn of Jordan unitary algebra structures on k n , k an algebraically closed field with char k 6= 2 , is studied, as well as infinitesimal deformations of Jordan algebras. Also we establish the list of ...

We define representations of weighted posets and construct for them reflection functors. Using this technique we prove that a weighted poset is of finite representation type if and only if its Tits form is weakly positive; ...