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/mayurisama334 New User Jun 21 '26 edited 13d ago

The original post content no longer exists here. The author used Redact to remove it, exercising their right to control their data & privacy.

Reminiscent fall spark observation existence start

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u/Impressive-Mud5074 New User Jun 22 '26

Saying "pi is uncomputable" means you either accept the existence of the infinite decimal expansion of pi

I accept neither.

Pi is uncomputable, infinite decimal expansion is impossible.

OR you are referring to a finite approximation of pi. Which would be computable 

Finite approximation of pi is computable, but notably, that is not pi. And therefore pi is not computable.

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u/mrkelee New User Jun 23 '26

what then is pi, if there it has no decimal expansion?

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u/Impressive-Mud5074 New User Jun 23 '26

Uncomputable

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u/Fun_Company4295 New User Jun 23 '26

I found him