Cantor's diagonal argument

:Note: in order to fully understand this article you may want to refer to the set theory portion of the table of mathematical symbols.

Why this does not work on integers

People sometimes think that the above proof can be adapted to the integers to show that they too are uncountable. They try to do this by dropping the decimal point in the expansions above. The trouble is that an infinite sequence of non-zero digits does not represent an integer. This is the reason for step (7) above.

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