Rational Number Space is Meager

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Theorem

Let $\struct {\Q, \tau_d}$ be the rational number space under the Euclidean topology $\tau_d$.


Then $\struct {\Q, \tau_d}$ is meager.


Proof

From Rational Numbers are Countably Infinite, $\Q$ is a countable union of singleton subsets.

From Singleton Set is Nowhere Dense in Rational Space, each of those singleton subsets is nowhere dense in $\struct {\Q, \tau_d}$.

The result follows from definition of meager.

$\blacksquare$


Sources