Example image of eyePlorer eyePlorer map for 'Countable set': Cardinal number Cardinality Mathematics Natural number Set (mathematics) Subset Uncountable set Georg Cantor Finite set Injective function Bijection Infinite set Surjective function Integer Real number Ordered pair Fraction (mathematics) Numerator Cartesian product Mapping Recursive Vector space Rational number Prime number Coprime Algebraic number Definable real number Axiom of countable choice Union (set theory) Disjoint Sequence Domain of a function Mathematical induction Cantor's theorem Power set Cantor's diagonal argument Cantor's first uncountability proof Finite intersection property Constructible universe Inner model Löwenheim–Skolem theorem Skolem's paradox Transcendental number Ordinal number Total order Well-order Hilbert's paradox of the Grand Hotel Axiom of countability Back-and-forth method Boole's inequality