Prove that |R−Z|=|R| where R is reals and Z is integers.
New approach
Maybe the problem is reduced to finding a bijection between (0,1) and [0,1] if we find a bijection between these intervals, we can do the same thing for the other ones
What about this possible bijective function f(x)=1/(x-1)x
Thank you so much for your help, I have more problems like this to work on, so need more help.
Answer
Assume it is known that any open, nonempty subset of R is uncountable - this step is where your work may be. The rest is easy:
Let S=R∖Z.
First remark that S⊂R, so we must have that |S|≤|R|.
The open interval (0,1) is a subset of S⊂R, so |(0,1)|≤|S|≤|R|.
But |R|=|(0,1)|, and we're done.
NOTE: to see that |R|=|(0,1)|, we might construct a bijection f:(0,1)⟶(0,∞) such that f(x)=11−x−1, and reason that this bijection can be easily extended to a bijection between (0,1) and R.
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