Limits of PGL(3)-translates of plane curves, I
arXiv:0706.1301 · doi:10.1016/j.jpaa.2009.06.010
Abstract
We classify all possible limits of families of translates of a fixed, arbitrary complex plane curve. We do this by giving a set-theoretic description of the projective normal cone (PNC) of the base scheme of a natural rational map, determined by the curve, from the of 3x3 matrices to the of plane curves of degree . In a sequel to this paper we determine the multiplicities of the components of the PNC. The knowledge of the PNC as a cycle is essential in our computation of the degree of the PGL(3)-orbit closure of an arbitrary plane curve, performed in our earlier paper "Linear orbits of arbitrary plane curves".
28 pages. Minor revision. Final version