"Quaternionic" . "sphere of square roots of minus one" . "quaternion algebra" . "'''H'''" . . . "Quaternions" . "unit quaternions" . "Quaternion" . . "the equation has infinitely many solutions" . "square roots of minus one" . . . . "quaternion" . . . "Quaternion#Conjugation, the norm, and reciprocal" . . "conjugate of the quaternion" . "Hamilton product" . "union of complex planes" . . . "quaternion algebras" . "quaternionic" . "scalar" . "quaternions" . . "rules on multiplication of quaternion basis elements" . "Quaternion#Hamilton product" . "conjugate quaternion" . . "quaternion imaginaries" . . . "quaternionic relations" . . . "see details" . "Quaternion#Scalar and vector parts" . . . "Imaginary quaternion unit" . "conjugate" . "Quaternion#Matrix_representations" . "Quarternionist" . "Work on quaternions" . "Quaternion" . "unit imaginary quaternion" . "algebra of quaternions" . "conjugation" . "quaternion multiplication" . . "norm" . . . "Quaternion#Square_roots" . . "scalar and vector parts" . "sphere of square roots of −1" . "appears as a union of complex planes" . "scalar part" . "unit-quaternions" . . . "infinitely many square roots" .