Definition:Topologically Equivalent Metrics/Definition 2

Definition
Let $M_1 = \struct {A, d_1}$ and $M_2 = \struct {A, d_2}$ be metric spaces on the same underlying set $A$.

$d_1$ and $d_2$ are topologically equivalent :


 * $U \subseteq A$ is $d_1$-open $\iff$ $U \subseteq A$ is $d_2$-open.

Also see

 * Equivalence of Definitions of Topologically Equivalent Metrics