The web resource on numerical range and numerical shadow

## Introduction

Combining the ideas of the restricted numerical range with the numerical shadow one is led in a natural way to the definition of a restricted numerical shadow, $$P^R_A(z) \ := \ \int_{R} {\rm d} \mu(\psi) \ \delta\Bigl( z-\langle \psi|A|\psi\rangle\Bigr) \ ,$$ where $R$ is a selected subset of ${\Omega}_N$, the set of size $N$ pure quantum states.

## Examples

For a full list of examples of restricted numerical shadows, go here: examples