Here Γ Γ ∗ ∗ t : T 0 [ − − ϵ ϵ , ϵ ϵ ] → → T Γ Γ ( t , 0 ) M = T γ γ ( t ) M is the tangent map of Γ Γ t : [ − − ϵ ϵ , ϵ ϵ ] → → M , where Γ Γ t ( ϵ ϵ ) = Γ Γ ( t , ϵ ϵ ) , and d d ϵ ϵ | ϵ ϵ = 0 ∈ ∈ T 0 [ − − ϵ ϵ , ϵ ϵ ] .