@@How this problem works

@@ABELIAN

\ni The equation can be treated as the system consisting of one 
equation, so we can use general method for solving systems over
abelian groups (see @Equations in abelian groups
@probs/EquationsInAbelianProblem::ABELIAN@).

\ni See also @General_abelian_groups@General_abelian_groups::General discussion@ for a general discussion of abelian groups.