González, Manuel; Martinón, Antonio Operational quantities characterizing semi-Fredholm operators. (English) Zbl 0830.47008 Stud. Math. 114, No. 1, 13-27 (1995). Summary: Several operational quantities have appeared in the literature characterizing upper semi-Fredholm operators. Here, we show that these quantities can be divided into three classes, in such a way that two of them are equivalent if they belong to the same class, and are comparable and not equivalent if they belong to different classes. Moreover, we give a similar classification for operational quantities characterizing lower semi-Fredholm operators. Cited in 1 ReviewCited in 5 Documents MSC: 47A53 (Semi-) Fredholm operators; index theories Keywords:upper semi-Fredholm operators; lower semi-Fredholm operators PDFBibTeX XMLCite \textit{M. González} and \textit{A. Martinón}, Stud. Math. 114, No. 1, 13--27 (1995; Zbl 0830.47008) Full Text: DOI EuDML