An exact proof term for the current goal is CD_exp_nat_2 {4} HSNo octonion_tag_fresh minus_HSNo conj_HSNo add_HSNo mul_HSNo HSNo_0 HSNo_1 minus_HSNo_0 conj_HSNo_0 conj_HSNo_1 add_HSNo_0L add_HSNo_0R mul_HSNo_0L mul_HSNo_1R.