Structure of the nucleus of 2201+315. The analysis of MOJAVE data with our minimization method suggests that the nucleus of 2201+315 contains three BHs. G is the center of gravity of the BBH system C0–C9 and L1 is the first Lagrange point of the BBH system C0–C9; this is the point where the gravitational forces of the BHs C0 and C9 are equal. In order to obtain a stable solution, the radii of the accretion disks around C0 and C9 have to be smaller than the distances L1–C0 and L1–C9, respectively.