 Expressive power. Since \(\mathbf{IFL}\) is not closed under contradictory negation, \(\mathbf{EIFL}\) is strictly more expressive than \(\mathbf{IFL}\) (cf. Subsect.  4.2).[62]  The following properties are expressible in \(\mathbf{EIFL}\) but not in \(\mathbf{IFL}\) (Hintikka 1996: 188–190): finiteness of the domain, well-foundedness of a binary relation, connectedness of a graph, principle of mathematical induction, Bolzano-Weierstrass theorem, and the topological notion of continuity.