Convexoid operator
In mathematics, especially operator theory, a convexoid operator is a bounded linear operator "T" on a complex Hilbert space "H" such that the closure of the numerical range coincides with the convex hull of its spectrum. An example of such an operator is a normal operator (or some of its generalization). A closely related operator is a spectraloid operator: an operator whose spectral radius coincides with its numerical radius. In fact, an operator "T" is convexoid if and only if formula_1 is spectraloid for every complex number formula_2.