Definition:Apotome

Definition
Let $a, b \in \left\{{x \in \R_{>0} : x^2 \in \Q}\right\}$ be the lengths of two rational line segments such that $a > b$.

Then $a - b$ is an apotome :
 * $(1): \quad \dfrac a b \notin \Q$
 * $(2): \quad \left({\dfrac a b}\right)^2 \in \Q$

where $\Q$ denotes the set of rational numbers.

Also see

 * Definition:Binomial (Euclidean)
 * Apotome is Irrational