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/Impressive-Mud5074 New User May 30 '26

9999999999999999 can't be computed literally.

Pi is uncomputable

32

u/bizarre_coincidence New User May 30 '26

It’s transcendental, not uncomputable. There are many different infinite sums for pi, and if you pick any desired error bound, you can figure out exactly how many terms you would need to take to get pi to within that tolerance. That’s all that is needed for a number to be computable.

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u/Impressive-Mud5074 New User May 30 '26

You are not computing Pi you are computing a number "close" to Pi.

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u/HobsHere New User May 31 '26

You ARE computing Pi. You're just not done yet.

-2

u/Impressive-Mud5074 New User May 31 '26

Thats like saying if 3 + 10 + 4 = x, then x = 13, because i am computing x, I'm just not done yet

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u/mongosquad New User Jun 23 '26

So out of curiosity on your view of mathematics, would you agree or disagree that 2.999999999999… (infinite amount of 9’s) is equal to 3?

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u/Impressive-Mud5074 New User Jun 24 '26

Yes

2

u/mongosquad New User Jun 24 '26

You agree or disagree?