Since the Weyl group acts by reflections on the CSA, they are isometries, so the degree 2 invariant polynomial is  where  is the dimension of the CSA , also known as the rank of the Lie algebra.
sˈɪns ðə wˈeɪl ɡɹˈuːp ˈækts baɪ ɹᵻflˈɛkʃənz ɔnðə sˌiːˌɛsˈeɪ, ðeɪ ɑːɹ aɪsˈɑːmətɹiz, sˌoʊ ðə dᵻɡɹˈiː tˈuː ɪnvˈɛɹiənt pˌɑːlɪnˈoʊmɪəl ɪz wˌɛɹ ɪz ðə dᵻmˈɛnʃən ʌvðə sˌiːˌɛsˈeɪ , ˈɔːlsoʊ nˈoʊn æz ðə ɹˈæŋk ʌvðə lˈaɪ ˈældʒᵻbɹə.