{"paper":{"title":"On singularities of  ${\\cal M}_{I\\!\\! P^3}(c_1,c_2)$","license":"","headline":"","cross_cats":["math.AG"],"primary_cat":"alg-geom","authors_text":"Giorgio Ottaviani, Vincenzo Ancona","submitted_at":"1995-02-13T17:18:43Z","abstract_excerpt":"Let ${\\cal M}_{I\\!\\! P^3}(c_1,c_2)$ be  the moduli space of stable rank-$2$ vector bundles on $I\\!\\! P^3$ with Chern classes $c_1$, $ c_2$. We prove the following results.\n  1) Let  $0 \\le \\beta < \\gamma $  be two integers, ($\\gamma \\ge 2)$, such that $2\\gamma-3\\beta>0$; then ${\\cal M}_{I\\!\\! P^3}(0,2\\gamma^2-3\\beta^2)$ is singular (the case $\\beta =0$ was previously proved by M. Maggesi).\n  2) Let $0 \\le \\beta < \\gamma $  be two odd integers ($\\gamma \\ge 5)$, such that $2\\gamma-3\\beta+1>0$; then ${\\cal M}_{I\\!\\! P^3}(-1,2(\\gamma/2)^2-3(\\beta/2)^2+1/4)$  is singular.\n  In particular ${\\cal M}_"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"alg-geom/9502008","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}