Under these circumstances, there is a "correct" use of the hypercomputer. While a civilization could use it to compute some strategy in a war, upload themselves into it for a form of immortality, or create a new world by instructing it to run some kind of Game of Life (https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life) program, a more practical use would be to compute the first few thousand digits of Chaitin's constant for a programming language. This is possible because we can finitely describe "attempt to run every possible source code and record if the result halts", we just need an infinite amount of time in order to finish the task. Importantly, although we can't know the exact value of \(\Omega\), the first few thousand digits are about just as good for mortal purposes.

I always imagined that, in the story, one civilization would be unsubtle and look down on the other, which would only want to use the hypercomputer for the "academic" purpose of knowing \(\Omega\) approximately, only to realize that this knowledge is possibly the most practical use of the machine.

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Conway's Game of Life - Wikipedia

When I learned about this as an undergraduate I started telling people the following story: Suppose that, simultaneously, two space-faring civilizations discover a naturally-occurring closed timelike curve (https://en.wikipedia.org/wiki/Closed_timelike_curve) around a nearby black hole. Suppose further that these civilizations both know that this structure can be used to build a hypercomputer (https://en.wikipedia.org/wiki/Hypercomputation), a machine that can perform an infinite number of classical computational steps in a finite amount of time. In order to make our story more realistic, we add the following constraints:

(1) The hypercomputer can correctly perform an infinite calculation, but it must be described by a finite program.
(2) The hypercomputer can access an arbitrarily large amount of memory during calculation, but there is a fixed finite size for its output after the infinite calculation is over.
(3) A massive amount of resources are needed for each use of the hypercomputer. Perhaps it breaks after each use.

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Closed timelike curve - Wikipedia

While organizing some files today I came across my copy of Charles H. Bennett's "On Random and Hard-to-Describe Numbers" from 1979 (https://www.worldscientific.com/doi/abs/10.1142/9789812770837_0001). It discusses Chaitin's constant (https://en.wikipedia.org/wiki/Chaitin%27s_constant) for a programming language, which is the probability \(\Omega\) that a randomly-chosen program will compile. This is a real number between 0 and 1 which is definable but not computable.

Bennett goes on to discuss the "Cabalistic" properties of \(\Omega\). Knowing the first few thousand digits of \(\Omega\) would allow one to decide practically all finitely refutable mathematical conjectures. Basically, \(\Omega\) is a very compact encoding of the Halting Problem (https://en.wikipedia.org/wiki/Halting_problem), so knowing its first \(n\) bits is enough to determine whether any program up to \(n\) bits in length would eventually halt. While there are some exceptions, many open problems in mathematics can be phrased in terms of the halting of some computer program of reasonably short length.

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@wikipedia:
…"a closed timelike curve (CTC) is a world line in a Lorentzian manifold, of a material particle in spacetime, that is "closed", returning to its starting point. This possibility was … later confirmed by Kurt Gödel … If CTCs exist, their existence would seem to imply at least the theoretical possibility of time travel backwards in time" …

🔗 https://www.youtube.com/watch?v=-DPPccz5BcY 03 Jan 2024
🔗 https://en.wikipedia.org/wiki/Closed_timelike_curve

#Community #TimeTravel #Research #closedtimelikecurve #spacetime #lorentz

Einstein's Timeloop: Untangling the Mind-Bending Physics of Closed Timelike Curves

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