The cardinality of $Q ∩ (0,∞) ≤$ the cardinality of $\Bbb R × \Bbb R$.
I know that the cardinality of $\Bbb R × \Bbb R$ is $c$, however I don't know how to simplify $Q ∩ (0,∞)$, it doesn't include the negative irrational numbers?
2026-04-12 08:01:39.1775980899
Cardinality of positive rationals
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This is the intersection of $Q$ with $(0,\infty)$, so the positive rationals. But all you really need for this question is the fact that it is a subset of $R$.