Is there a common way to express the idea of "$\pm 1$" using words, ideally without spelling out "plus or minus one". Not that the absolute value is one, but that the value is either 1 or -1.
For example, without using the symbols "$\pm 1$", how would one say "If $Q \in M_{n \times n}(\mathbb{R})$ is orthogonal, then $\det(Q) = \pm 1$"?
What about $|\det(Q)| = 1$? Isn't it equivalent to $\det(Q) = \pm 1$ ? Or would you prefer "$\det(Q)$ of square $1$"?