2022/06/05 by Qixiao He, He, Qixiao, Ilya M. Spitkovsky +3
Computer Science · Mathematics · #15A60 15B57 15B99 #Advanced Topics in Algebra #FOS: Mathematics #Functional Analysis (math.FA) #Holomorphic and Operator Theory #Matrix Theory and Algorithms
paper · pdf · doi:10.48550/arxiv.2206.02141
openalex publication_date 2022/06/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Two statements concerning n-by-n partial isometries are being considered: (i) these matrices are generic, if unitarily irreducible, and (ii) if nilpotent, their numerical ranges are circular disks. Both statements hold for n≤ 4 but fail starting with n=5.