Computation of antieigenvalues (Q2570956)

Using several results due to M. G. Krein (1969), P. R. Halmos (1982) and G. De Barra (1981) and the Lagrange multiplier method, the author establishes some formulas for the first antieigenvalue \[ \mu_1(T)=\displaystyle\text{inf}_{Tf\not=0}\displaystyle\frac{\text{Re}(Tf,f)}{\| Tf\| \| f\| } \] of a strictly accretive operator \(T\).