“…where the left-invariant vector fields { ∂ ∂x i , H i , V α , W α } form a local basis of G × K M. The vector fields H i , V α , W α and the index R + M are determined by G and K. For more details, see [5], [28]. Let {dx i , ν i , dV α , dW α } 1≤i≤n,α∈R + M be the dual 1-form of the basis.…”