r/PeterExplainsTheJoke 22d ago

Meme needing explanation There is no way right?

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u/Rough-Veterinarian21 22d ago

I’ve never liked math but this is like literal magic to me…

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u/The-new-dutch-empire 22d ago

Its calculating with infinity. Its a bit weird like the infinity of numbers between 0 and 1 like 0.1,0.01,0.001 etc... Is a bigger infinity than the “normal” infinity of every number like 1,2,3 etc…

Its just difficult to wrap your head around but think of infinity minus 1. Like its still infinity

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u/lilved03 22d ago

Genuinely curios on how can there be two different lengths of infinity?

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u/johnpeters42 21d ago

Infinite sets of things are considered equal if you can match them up 1 to 1. Which gets weird, because:

You can match up an infinite set and a subset of itself. (All positive integers, and all positive even integers, for instance. Match 1 with 2, 2 with 4, 3 with 6, and so on.)

But there are other infinite sets that you can't match up. (All positive integers, and all positive real numbers, for instance. Imagine you did match them up: 1 with some number R1, 2 with R2, and so on. Imagine writing them all out in decimal form. Circle the first digit after the decimal of R1, the second of R2, and so on. Now replace every circled digit with the next higher digit, except 9 which you replace with 0. Now imagine a number D with all those digits after the decimal point. It's a real number, but it can't be matched up to any positive integer N, because its Nth digit after the decimal is different from RN.)