Resumen de Note on operational quantities and Mil'man isometry spectrum

Manuel González Ortiz, Antonio Martinón Cejas

• In this note, using Mil 'man isometry spectrum and some Tsirelson-like examples of Banach spaces, due to Figiel and Johnson, and Schlumprecht, we show that two operational quantities that have been used to characterize upper semi-Fredholm operators, are not equivalent.