Frisch–Waugh–Lovell theorem
In statistics and econometrics, the Frisch–Waugh–Lovell (FWL) theorem proves a property of ordinary least squares estimators. The theorem is named for econometricians Ragnar Frisch, Frederick V. Waugh, and Michael C. Lovell.
Source: Wikipedia — Frisch–Waugh–Lovell theorem (CC BY-SA 4.0)