- $ \\\exists x \\\in \\\mathbb{R}:x + \\\left( { - x} \\\right) = 0$.
- $ \\\forall x \\\in \\\mathbb{R}:x + \\\left( { - x} \\\right) = 0$.
- $ \\\vee x \\\in \\\mathbb{R},x + \\\left( { - x} \\\right) = 0$.
- $ \\\exists x \\\in \\\mathbb{Z},x - x = 0$.