# Cantor's diagonal argument

## Primary tabs

Synonym:
Cantor's diagonalization
Type of Math Object:
Topic
Major Section:
Reference
Groups audience:

## Mathematics Subject Classification

03E10 Ordinal and cardinal numbers

### oops

In my correction, I said

X is n (a natural number) such that n \in X only if n \not\in N_x

This should be

X is n (a natural number) such that n \in X only if n \not\in N_n

sorry.

-apk

### Re: oops

Ah, I see the usage now. I'll file a more complete entry on the 'morrow. =)

### Cantor Diagonal

If "between" means "strictly between" then you want to add "make at least one ci not zero" . For example you might choose c1 first and make it not zero.

### Cantor’s diagonal argument

In the same manner, write a full list of rational numbers. How can you proof that the missing numbers Cantor constructs are all irrationals? Can you proof that, for every n, you can’t find at least one rational x, missing from the sequence?