Equation Icon  [ ] dr2 ∑2 ds2 = Γ (𝜃) − r2dt2 + ---+ α(𝜃)2d𝜃2 + γij(𝜃 )2(dϕi + kirdt)(dϕj + kjrdt) , (36 ) r2 i,j=1 2 A A I ∑ I i eI i χ = χ (𝜃), A = fi (𝜃 )(dϕ + kirdt) − kidϕ . i=1