Paragraph

1. \(\{x \st x + 3 \in \N\}\text{.}\)

2. \(\{x \in \N \st x + 3 \in \N\}\text{.}\)

3. \(\{x \st x \in \N \vee -x \in \N\}\text{.}\)

4. \(\{x \st x \in \N \wedge -x \in \N\}\text{.}\)