Comment Re:it's been said (Score 1) 278
The rational numbers are infinite, the irrational numbers are infinite, add them together and you have the real numbers, which is a "larger" infinite set than the rational numbers (and probably the irrationals, though I can't say for sure since I've never attempted that proof).
Quite right. There are two types of infinite cardinality: countable and uncountable. Countable encompasses the set of rational numbers, and calculable irrationals such as roots and all polynomial combinations of the those for which there is an isomorphic map onto the set of integers. Then there's the greater set, the uncountably infinite, e.g. the transcendental numbers and their ilk.
I doubt the cardinality of real numbers would be greater than irrationals themselves, since most numbers are transcendental. It'd be like taking a teaspoon of water out of the ocean and wondering if it's still the ocean.
To be pedantic, the transcendentals are also countably infinite. The integers, rationals, algebraic irrationals, transcendentals, and quite a few others all fall under the heading of "computable numbers", i.e. numbers whose exact solution can be arrived at by a Turing machine given infinite time and tape. Even though it sounds like a ridiculously large set, the set of computable numbers is countable: for any Universal Turing Machine you like, each computable number maps to the natural number that encodes the initial tape for the UTM such that the UTM simulates any one of the TMs that can generate the computable number in question.
For instance, even though pi is a transcendental and has no algebraic representation, there are well-known algorithms that iteratively generate as many digits of pi as you like. The infinite series of pi digits can thus be replaced with a (finite) computer program implementing one of these algorithms, and any finite series of pi digits can be replaced by the same algorithm plus the number of digits to stop at. A finite approximation of pi is merely cached output from the computer program, and therefore {program U finite approximation} adds no new information beyond {program} to help you distinguish pi from the other real numbers, meaning you can uniquely identify pi with just the computer program and no further information.