Definition:Metric Space/Triangle Inequality

Definition
Let $M = \left({A, d}\right)$ be a metric space, satisfying the metric space axioms:

Axiom $M2$ is referred to as the triangle inequality, as it is a generalization of the Triangle Inequality which holds on the real number line and complex plane.

Also see

 * Reverse Triangle Inequality:
 * $\forall x, y, z \in X: \left|{d \left({x, z}\right) - d \left({y, z}\right)}\right| \le d \left({x, y}\right)$