Equation Icon  2 α α − ℓ Gˆμν = 2ℓ(ˆ∇ μˆ∇ νℓ − ˆgμν∇ˆ ∇ˆα ℓ) + 3ˆgμν(ˆ∇ ℓ)ˆ∇ αℓ. (50 )