{"paper":{"title":"The numerical measure of a complex matrix","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["math.PR","math.SP"],"primary_cat":"math.FA","authors_text":"Denis Serre, Thierry Gallay","submitted_at":"2010-09-08T13:10:04Z","abstract_excerpt":"We introduce and carefully study a natural probability measure over the numerical range of a complex matrix $A \\in M_n(\\C)$. This numerical measure $\\mu_A$ can be defined as the law of the random variable $<AX,X> \\in \\C$ when the vector $X \\in \\C^n$ is uniformly distributed on the unit sphere. If the matrix $A$ is normal, we show that $\\mu_A$ has a piecewise polynomial density $f_A$, which can be identified with a multivariate $B$-spline. In the general (nonnormal) case, we relate the Radon transform of $\\mu_A$ to the spectrum of a family of Hermitian matrices, and we deduce an explicit repres"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1009.1522","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"}