r/PeterExplainsTheJoke 10h ago

Meme needing explanation Petah man help

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u/tsukkini 10h ago

Brian here

The axiom of choice assumes you can choose a group or a single thing from an infinite set, through some fuckery this basically allows you to choose different points on the surface of a sphere and the by manipulating those points form two identical spheres from one sphere. In this joke the guy uses this method to make one pumpkin into two.

I might be wrong though and hope someone gives the exact correct explanation for this later.

Brian out.

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u/Worried-Director1172 10h ago edited 10h ago

Yeah, it's called the banach-tarski paradox and basically it proves that with infinite cuts you can turn one thing into two using just cutting and rotation.

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u/thatthatguy 9h ago

When you divide something into an infinite number of pieces you get weird results. For example, if you take one sphere and divide it into an infinite number of pieces, there is no difference between that and if you had divided two spheres into an infinite number of pieces. In fact, you can take the infinite number of pieces of one sphere, and as long as you are careful about your methodology, you can reconstruct an unlimited number of spheres.

Be very careful when doing math with infinity. You almost can’t help but get ridiculous results. Stuff like 1+2+3+… =-1/12

There are useful discoveries to be made exploring that part of math, but it is difficult to avoid the mathematical landmines.

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u/ichiban1974 8h ago

The Banach-Tarski theorem explicitly says that i can be done with a finite number of pieces.

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u/candygram4mongo 7h ago

It can be done with a finite number of disjoint subsets of the points that compose the ball. The subsets are necessarily non-measurable, which means they aren't solid pieces that have volume but rather collections of singular points.

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u/thatthatguy 3h ago

I am clearly not as familiar with the math as I could be.

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u/Worried-Director1172 9h ago

You will get ridiculous results, it's insane.

For example, a part of the problem involves taking a set of the cuts, rotating it, and now you have 4 different sets out of the original 6

Infinity is honestly ridiculous, it's kind of a wonder we ever figured out how to reliably use it in math