Power Set of Natural Numbers has Cardinality of Continuum/Proof 1
Theorem
Let $\N$ denote the set of natural numbers.
Let $\powerset \N$ denote the power set of $\N$.
Let $\card {\powerset \N}$ denote the cardinality of $\powerset \N$.
Let $\mathfrak c = \card \R$ denote the cardinality of the continuum.
Then:
- $\mathfrak c = \card {\powerset \N}$
Proof
Outline
$\powerset \N$ is demonstrated to have the same cardinality as the set of real numbers.
This is done by identifying a real number with its basis expansion in binary notation.
Such a basis expansion is a sequence of $0$s and $1$s.
Each $1$ of a real number $x$ expressed in such a way can be identified with the integer which identifies the power of $2$ representing the $1$ in that place.
Hence $x$ corresponds to the subset of $\N$ whose elements are the positions in $x$ which hold a $1$.
Thus $\R$ and $\powerset \N$ are equivalent.
From the Cantor-Dedekind Hypothesis, the real numbers are in one-to-one correspondence with the points on a line segment.
The points on a line segment form a continuum.
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