Definition:Quaternion Modulus

Definition
Let $\mathbf x = a \mathbf 1 + b \mathbf i + c \mathbf j + d \mathbf k$ be a quaternion, where $a, b, c, d \in \R$.

Also see

 * Equivalence of Definitions of Quaternion Modulus


 * Quaternion Modulus is Norm
 * Definition:Modulus of Quaternion-Valued Function


 * Quaternion Modulus in Terms of Conjugate: $\size {\mathbf x} := \sqrt {\mathbf x \overline {\mathbf x} }$ where $\overline {\mathbf x}$ denotes the quaternion conjugate of $\mathbf x$