Equation Icon  μ−λ----v----- ∘ ------2-μ−λ x- e ∘ 1 + |v|2 ⋅ ∇xf − 1 + |v| e μr r ⋅ ∇vf = 0, (55 ) −2λ 2 e (2rλr − 1) + 1 = 8πr ρ, (56 ) e−2λ(2rμ + 1) − 1 = 8πr2p. (57 ) r