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Cosmologically Unique IDs

jasonfantl.com

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Re: Cosmologically Unique IDs

#31

Post by AlotOfReading »

bluecoconut wrote: post #5

Fun read. One upside of the deterministic schemes is they include provenance/lineage. Can literally "trace up" the path the history back to the original ID giver. Kinda has me curious about how much information is required to represent any arbitrary provenance tree/graph on a network of N-nodes/objects (entirely via the self-described ID)? (thinking in the comment: I guess if worst case linear chain, and you assume t…

Two ways to frame it:

Provenance is a DAG, so you get a partial order for free by topological sort. That can be extended to a compatible total order. Then provenance for a node is just its ordering. This kind of mapping from objects to the first N consecutive naturals is also a minimal perfect hash function, which have n log n overhead. We can't navigate the tree to track ancestry, but equality implies identical ancestry.

Alternatively, we could track the whole history in somewhat more bits with a succinct encoding, 2N if it's a binary tree.

In practice, deterministic IDs usually accept a 2^-N collision risk to get log n.

Re: Cosmologically Unique IDs

#32

Post by frikit »

Sharlin wrote: post #23
u1hcw9nx wrote: post #15

Earlier quoted context omitted.

You must consider both time and locality. From now until protons decay and matter does not exist anymore is only 10^56 nanoseconds.

If protons decay. There isn't really any reason to believe they're not stable.

Protons can decay because the distinction between matter and energy isn't permanent.

Two quarks inside the proton interact via a massive messenger particle. This exchange flips their identity, turning the proton into a positron and a neutral pion. The pion then immediately converts into gamma rays.

Proton decayed!

Re: Cosmologically Unique IDs

#34

Post by zamadatix »

rubyn00bie wrote: post #20
u1hcw9nx wrote: post #15

Earlier quoted context omitted.

You must consider both time and locality. From now until protons decay and matter does not exist anymore is only 10^56 nanoseconds.

I got a big laugh at the “only” part of that. I do have a sincere question about that number though, isn’t time relative? How would we know that number to be true or consistent? My incredibly naive assumption would be that with less matter time moves faster sort of accelerating; so, as matter “evaporates” the process accelerates and converges on that number (or close it)?

Times for things like "age of the universe" are usually given as "cosmic time" for this reason. If it's about a specific object (e.g. "how long until a day on Earth lasts 25 hours") it's usually given in "proper time" for that object. Other observers/reference frames may perceive time differently, but in the normal relativistic sense rather than a "it all needs to wind itself back up to be equal in the end" sense.

Re: Cosmologically Unique IDs

#35

Post by u1hcw9nx »

lisper wrote: post #27
Etheryte wrote: post #22

Earlier quoted context omitted.

That's such an odd way to use units. Why would you do 10^56 * 10^-9 seconds?

This was my thought. Nanoseconds are an eternity. You want to be using Planck units for your worst-case analysis.

If you go far beyond nanoseconds, energy becomes a limiting factor. You can only achieve ultra-fast processing if you dedicate vast amounts of matter to heat dissipation and energy generation. Think on a galactic scale: you cannot have even have molecular reaction speeds occurring at femtosecond or attosecond speeds constantly and everywhere without overheating everything.

Re: Cosmologically Unique IDs

#36

Post by idiotsecant »

rubyn00bie wrote: post #20
u1hcw9nx wrote: post #15

Earlier quoted context omitted.

You must consider both time and locality. From now until protons decay and matter does not exist anymore is only 10^56 nanoseconds.

I got a big laugh at the “only” part of that. I do have a sincere question about that number though, isn’t time relative? How would we know that number to be true or consistent? My incredibly naive assumption would be that with less matter time moves faster sort of accelerating; so, as matter “evaporates” the process accelerates and converges on that number (or close it)?

The local reference frame (which is what matters for proton decay) doesn't see an outside world moving slower or faster depending on how much mass is around it to any significant degree until you start adding a lot of mass very close around.

Re: Cosmologically Unique IDs

#37

Post by frikit »

The best way to solve this is not to, and just giving up on the idea of identification.

If you have an infinite multiverse of infinite universes, and perhaps layers on that, with different physics, etc., you can’t have identity outside of all existence.

In Judaism, one/the name of God is translated as “I am”. I believe this is because God’s existence is all, transcending whatever concepts you have of existence or of IDs. That ID is the only ID.

So, the cosmic solution to IDs is the name of God.

Re: Cosmologically Unique IDs

#38

Post by lisper »

u1hcw9nx wrote: post #35
lisper wrote: post #27

Earlier quoted context omitted.

This was my thought. Nanoseconds are an eternity. You want to be using Planck units for your worst-case analysis.

If you go far beyond nanoseconds, energy becomes a limiting factor. You can only achieve ultra-fast processing if you dedicate vast amounts of matter to heat dissipation and energy generation. Think on a galactic scale: you cannot have even have molecular reaction speeds occurring at femtosecond or attosecond speeds constantly and everywhere without overheating everything.

Maybe. It's not clear whether these are fundamental limits or merely technological ones. Reversible (i.e. infinitely efficient) computing is theoretically possible.

Re: Cosmologically Unique IDs

#39

Post by mock-possum »

frikit wrote: post #37

The best way to solve this is not to, and just giving up on the idea of identification. If you have an infinite multiverse of infinite universes, and perhaps layers on that, with different physics, etc., you can’t have identity outside of all existence. In Judaism, one/the name of God is translated as “I am”. I believe this is because God’s existence is all, transcending whatever concepts you have of existence or of…

which name of god though - there are hundreds, and were right back at the same place of struggling to come up with a unique identifier.

Re: Cosmologically Unique IDs

#40

Post by drchickensalad »

ekipan wrote: post #18

I forget the context but the other day I also learned about Snowflake IDs [1] that are apparently used by Twitter, Discord, Instagram, and Mastodon. Timestamp + random seems like it could be a good tradeoff to reduce the ID sizes and still get reasonable characteristics, I'm surprised the article didn't explore there (but then again "timestamps" are a lot more nebulous at universal scale I suppose). Just spitballing…

That also looks like the widely used BSON ids, to anyone else interested
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