Bekenstein further found that AQUAL can be obtained as the nonrelativistic limit of a relativistic field theory. This theory is written in terms of a Lagrangian that contains, in addition to the Einstein–Hilbert action for the metric field g μ μ ν ν , terms pertaining to a unit vector field u α α and two scalar fields σ σ and ϕ ϕ , of which only ϕ ϕ is dynamical. The TeVeS action, therefore, can be written as