Definition:Discrete Extension of Reals/Rational

Definition
Let $\struct {\R, \tau_d}$ be the real number line with the usual (Euclidean) topology.

Let $\Q$ denote the set of rational numbers.

Let $\tau^*$ be the discrete extension of $\struct {\R, \tau_d}$:
 * $\tau^* = \tau_d \cup \gen {\set x: x \in \Q}$

$\tau^*$ is then referred to as the discrete rational extension of $\R$.

Also see

 * Definition:Discrete Irrational Extension of Reals


 * Definition:Pointed Extension of Reals:
 * Definition:Pointed Rational Extension of Reals
 * Definition:Pointed Irrational Extension of Reals


 * Definition:Indiscrete Extension of Reals:
 * Definition:Indiscrete Rational Extension of Reals
 * Definition:Indiscrete Irrational Extension of Reals