Steveh15 said:
Maybe some of you really clever Maths people would like to explain to me how there are different sizes of infinity? I attended a lecture with some maths proffessors teaching 'fun' maths but I forgot the reasoning behind it, thought it was pretty cool.
Things like..
You have a hotel with an infinite number of rooms and each one is occupied with a guest, what do you do when..
a) one person comes to the hotel asking for a room?
b) and infinite number of people come to the hotel asking for a room?
I can remember the answers to these two, but can't really explain it.
I find this one of the most interesting parts of theoretical mathematics (I'd like to think that's the geekiest thing I've ever said but I'm sure it isn't).
At it's most basic it's to do with the difference between counting the natural numbers (1,2,3 etc) and the real numbers (every number that is not an imaginary number - if that doesn't make sense then just consider it every number).
Natural numbers are said to be countable and (this is where your belief may falter), there are the same number of even numbers as there are natural numbers. Think about that - the sequences (1,2,3...) and (2,4,6...) have the same number of elements. It might seem strange, but that is also the answer to your infinite hotel problem.
Real numbers are said to be uncountable. The basic premise is that there are more numbers between 0 and 1 than there are natural numbers. Lets say it was possible to count up to infinity, and you assigned a decimal between 0 and 1 to each natural number. The full explanation is very long winded but consider that whichever decimal you had you could always add a digit to the end to make a different one.
So your hotel problem has the first, smaller number of rooms, but it could not fit the second larger number into it, only more of the first.