- $ \\\forall n \\\in {\\\text{N}}:n \\\leqslant 2n$
- $ \\\exists x \\\in {\\\text{R}}:x > {x^2}$
- $ \\\exists n \\\in {\\\text{N}}:{n^3} = n$
- $ \\\forall x \\\in {\\\text{R}}:{x^2} > 0$