<p>
This example shows the basic usage of the multilevel functions in
-<tt>deal.II</tt>. It solves Helmholtz equation with Neumann boundary conditions
+<tt>deal.II</tt>. It solves the Helmholtz equation with Neumann boundary conditions
to avoid additional complications due to Dirichlet boundary conditions (there,
-some library functionsare missing). In all other respects, it is similar to
+some library functions are missing). In all other respects, it is similar to
step 5.
</p>
<li>MGTransfer, the object handling transfer between grids
<li>MGCoarse, the solver on the coarsest level
<li>MGSmoother, the smoother on all other levels
-<li>MGMatrix, the matrix object having a special level multipplication.
+<li>MGMatrix, the matrix object having a special level multiplication, i.e. we
+basically store one matrix per grid level and allow multiplication with it.
</ul>
</p>
<p>
These objects are combined in an object of type Multigrid, containing the
implementation of the V-cycle, which is in turn used by the preconditioner
-PreconditionMG, ready for plug-in into a linear slver of the LAC library.
+PreconditionMG, ready for plug-in into a linear solver of the LAC library.
</p>
<p>