ArXiv links to recent papers:
Benjamin J. Howard:
Matroids and Geometric Invariant Theory of torus actions
on flag spaces
In the paper "The projective invariants of ordered points on the
line" we find generators for the ideal of relations in
the projective invariants of n ordered points on the
projective line (Alfred B. Kempe (1894) discovered that the lowest
degree invariants generate).
We find that the relations are generated by the relations of degree four and
less. The relations we find are not as satisfactory as we would like
them to be, however, since we chose a
linearly independent set of generators, thus disrupting possible symmetries.
Practically one must use a computer to list them all.
The second paper, "The moduli space of n points on the line
is cut out by quadrics when n is not six",
is about a very simple and symmetric set of relations (they are linear and
quadric) that cut out the
moduli space scheme-theoretically, except for the case of
six points, where one needs a cubic relation. We conjecture that these
simple relations also generate the ideal.