Continuum (set theory)
In the mathematical field of
real numbers, or the corresponding (infinite) cardinal number
, denoted by .[1][2] Georg Cantor proved that the cardinality is larger than the smallest infinity, namely, . He also proved that is equal to , the cardinality of the natural numbers
.
The natural numbers, , or alternatively, that .[1]
Linear continuum
According to
Raymond Wilder
(1965), there are four axioms that make a set C and the relation < into a linear continuum:
- C is simply orderedwith respect to <.
- If [A,B] is a cut of C, then either A has a last element or B has a first element. (compare Dedekind cut)
- There exists a non-empty, countable subset S of C such that, if x,y ∈ C such that x < y, then there exists z ∈ S such that x < z < y. (separability axiom)
- C has no first element and no last element. (Unboundedness axiom)
These axioms characterize the
real number line
.
See also
- Aleph null
- Suslin's problem
- Transfinite number
References
- ^ a b Weisstein, Eric W. "Continuum". mathworld.wolfram.com. Retrieved 2020-08-12.
- ^ "Transfinite number | mathematics". Encyclopedia Britannica. Retrieved 2020-08-12.
Bibliography
- Raymond L. Wilder (1965) The Foundations of Mathematics, 2nd ed., page 150, John Wiley & Sons.