TODO

=== Enumeration ===

By now we do a full enumeration of the first minor with >= 7 elements.
But it is sufficient to consider only those with |T_1| <= |T_2|.

=== Violator Search ===

After finding that row 0 leads to t.u.,
do not try to remove row 0 in next iteration (i.e. after removing something else)

Try to achieve square matrices to be able to calculate determinant for short cut.

=== Parallel implementation ===

Where to parallelize:
* Decomposed parts
* Signing procedure in parallel to matroid decomposition
* Enumeration of (3|4)-separations.

=== Extension of sequence of nested minors ===

At the moment, the sequence is constructed for the whole matrix
and tested for (co)graphicness afterwards. This is not necessary,
since we only need the sequence until a minor is not cographic
and not graphic anymore.

Furthermore we can apply heuristics for the extension:
Always choose an extension which is non-graphic.
For single-row-extensions this is relatively hard but
all others should be easy.