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That doesn't actually follow- even though the reals are uncountable, they're what's called "separable", which means that there is a countable set which is "arbi
by roserevealed 2y ago
That doesn't actually follow- even though the reals are uncountable, they're what's called "separable", which means that there is a countable set which is "arbitrarily good at approximating them", basically- the rationals!
So even though there are uncountable reals, for any real number, you can find rational numbers that get arbitrarily close. You can actually see this pretty easily if you think of reals in decimal notation- sqrt(2) is irrational, but
1.4, 1.41, 1.414, 1.4142, 1.41421, 1.414123, ... etc are all rational numbers that get closer and closer to sqrt(2).
So you should think of real numbers as uncountable, but nonetheless surrounded by rationals no matter how close you zoom in.
- pfdietz 2y agoNot even the rationals are needed here. Just the rationals whose denominators are powers of two, for example, will do it (these have binary representations with a finite number of digits).