  We propose the method for obtaining invariants of arbitrary representations
of Lie groups that reduces this problem to known problems of linear algebra.
The basis of this method is the idea of a special extension of the
representation space, which allows us to regard it as a coalgebra of some Lie
algebra. In its turn, this allows us to reduce the problem of constructing
invariants of a given representation to the problem of constructing invariants
of the coadjoint representation of the corresponding Lie group. In our previous
paper it was shown that this problem can always be solved in a natural way by
the methods of linear algebra.
