Mixed formulations are also used in computational electromagnetics. These formulations use different formulations that are more suitable for specific computation domains. One of the most famous mixed formulations is the A–Vm formulation, which is a combination of The A Formulation and The Vm Formulation. In this mixed formulation, The A Formulation is used to model current-carrying domains, and The Vm Formulation is used to model the air gap and other nonconducting domains. The two formulations are coupled on their common interfacing boundaries. The A–Vm formulation is used by The Rotating Machinery, Magnetic Interface.