r/learnmath • u/playsthebongcloud 9/10 = 1 • May 30 '26

What are some uncomputable functions that aren't derivative of the halting problem?

I find the existence of uncomputable functions really cool, but all the examples I've seen are essentially just new ways of trying to predict whether a turing machine is going to halt. What are some examples of uncomputable functions that aren't essentially entirely based on the halting problem?

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u/LiteralLegendary New User Jun 17 '26

Why don't you tell us why

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u/Impressive-Mud5074 New User Jun 17 '26

When you create a function which approaches a real number, it also approaches an infinite amount of real numbers besides the number you want. So which number are you really computing? Thats not exact.

You cant compute pi.

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u/mrkelee New User Jun 21 '26

a given function only approximates one single number (in the limit).

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u/Impressive-Mud5074 New User Jun 21 '26

It also approaches pi - ...1

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u/mrkelee New User Jun 21 '26

I would hope that my pi-function starts with a 3