# Continuity axiom

From Encyclopedia of Mathematics

The axiom expressing in one way or another the continuity of the set of real numbers (cf. Real number). The continuity axiom for the real numbers can be stated, e.g., in terms of cuts: Every cut of the real numbers is determined by some number (Dedekind's axiom); in terms of nested closed intervals: Every family of nested closed intervals has a non-empty intersection (Cantor's axiom); and in terms of upper or lower bounds of sets: Every non-empty set that is bounded from above has a finite least upper bound, and every set that is bounded from below has a greatest lower bound (Weierstrass' axiom).

#### Comments

See also Cut; Dedekind cut.

**How to Cite This Entry:**

Continuity axiom.

*Encyclopedia of Mathematics.*URL: http://encyclopediaofmath.org/index.php?title=Continuity_axiom&oldid=16869

This article was adapted from an original article by L.D. Kudryavtsev (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article