“…However, in general, the symmetric space N χ 2 (ξ) does not coincide with N ξ . For example, in SU(5) the two following situations can occur: for ξ = 5H 1 , we have χ 2 (ξ) = 5H 2 , N ξ = Gr (1,5) and N χ 2 (ξ) = Gr(2, 5); on the other hand, for η = 3H 1 + H 2 + 5H 3 , we have N η = N χ 2 (η) = Gr (2,5).…”