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doogliusyesterday at 7:08 PM1 replyview on HN

If one wants to start talking cosmology, it's unlikely to the case that arbitrarily long-lived computers are possible, I don't think any of the theories in [0] are conducive to either an infinite-time or infinite-memory computer, so the strict mathematical definition for Big-O doesn't hold up. IMO it's better to use Big-O as an effective theory for predicting runtime on human-scale computers than take the mathematical formalism too literally.

[0] https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe?...


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jychangyesterday at 9:13 PM

> infinite-time or infinite-memory computer

That doesn't apply for the Bekenstein Bound though.

Literally the first line of the wikipedia article:

> In physics, the Bekenstein bound (named after Jacob Bekenstein) is an upper limit on the thermodynamic entropy S, or Shannon entropy H, that can be contained within a given *finite* region of space which has a *finite* amount of energy—or equivalently, the maximum amount of information that is required to perfectly describe a given physical system down to the quantum level.

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