I'm trying to grasp Cantor's diagonal argument to understand the proof that the power set of the natural numbers is uncountable. On Wikipedia, there is the following illustration:
The explanation of the proof says the following:
By construction, s differs from each sn, since their nth digits differ (highlighted in the example). Hence, s cannot occur in the enumeration.
I don't understand why the sequence
s at the bottom cannot occur anywhere in the enumeration of sequences above. I have read the proof about five times, but I'm still not getting it. I think I'm having an error in reasoning. Could someone please explain me why
s cannot be in the enumeration with an example?