Operators and Matrices · Volume 2, Issue 2 Higher-rank numerical range in infinite-dimensional Hilbert space 02-16 Pages 249-264 DOI 10.7153/oam-02-16 Downloads Short PDF Full PDF PNG Authors Rubén A. Martínez-Avendaño Keywords Higher-rank numerical range selfadjoint operator nonunitary isometry Subject classes 47A12 47B15 15A60