{ "id": "2111.06351", "version": "v1", "published": "2021-11-11T18:03:43.000Z", "updated": "2021-11-11T18:03:43.000Z", "title": "GIT stability of linear maps on projective space with marked points", "authors": [ "Max Weinreich" ], "comment": "32 pages", "categories": [ "math.AG", "math.DS" ], "abstract": "We construct moduli spaces of linear self-maps of $N$-dimensional projective space with $n$ marked points, up to projective equivalence. That is, we let the special linear group act simultaneously by conjugation on projective linear maps and diagonally on $(\\mathbb{P}^N)^n$, and we take the geometric invariant theory (GIT) quotient. These moduli spaces arise in algebraic dynamics in two ways: first, as ambient varieties of degree 1 portrait spaces; second, as the domains of discrete integrable systems such as the pentagram map. Our main result is a dynamical characterization of the GIT semistable and stable loci in the space of linear maps with marked points. The proof is combinatorial: to describe the weight polytopes for this action, we compute the vertices and facets of certain convex polyhedra generated by roots of the $A_N$ lattice.", "revisions": [ { "version": "v1", "updated": "2021-11-11T18:03:43.000Z" } ], "analyses": { "subjects": [ "37P45", "14L24", "52B05" ], "keywords": [ "linear maps", "marked points", "projective space", "git stability", "special linear group act" ], "note": { "typesetting": "TeX", "pages": 32, "language": "en", "license": "arXiv", "status": "editable" } } }