Suppose two beings are omniscient about Earth but not each other. One wants to point out one specific living human being on this planet to the other.
They must do this in the minimum number of ASCII characters such that they can be quite confident the other being will know exactly who they are referencing.
No previous common knowledge except common knowledge of the planet Earth and everything that can be logically deduced from that common knowledge.
Now suppose you pick a given person. How would you evaluate whether a proposed string has this property?
If they had a pre-agreed codebook, you’d need roughly log₂(8×10⁹) ≈ 33 bits ≈ 5 ASCII characters to index any human. If they are logically omniscient and omniscient about Earth, but do not have a pre-agreed codebook, how good can they get at minimax? How close to five chars?
If they can find a Schelling codebook they might be able to get the perfect 5 ascii chars for each person. But I’m not sure one exists. (perhaps birth time? encoded how?)
Even with a Schelling codebook, the 5 ascii char approach is dangerous because there are some 5-character strings that would suggest some other scheme is being used. For example, the guesser might have to assume the string weiyi is referring to the Chinese chess player (the most prominent person with that name by far) and not a codebook entry.
On the other hand, maybe being “logically omniscient,” the guesser would inevitably conclude that a codebook is the only reasonable scheme, and that would outweigh the enormous coincidence of the 5-character string so clearly identifying a person in English.
On the other hand, maybe being “logically omniscient,” the guesser would inevitably conclude that a codebook is the only reasonable scheme, and that would outweigh the enormous coincidence of the 5-character string being a valid name.
I don’t think this would be true because the string chooser picks a string after they know which person they are trying to point to
So, given that they need to point to Wei Yi, they might choose to use the name instead of the Schelling codebook if the Schelling codebook has a lower success probability than the name (even if the Schelling point is quite unique!). This is not a repeated game.
It’s hard to say what a UDT agent would do, though. It could go either way.
Via Unix time (milliseconds from Jan 1st 1970), and you can just trim whatever precision you don’t need. People are born with rate of 2/second, so you don’t need last 2 digits. Current timestamp is 10 digits long for seconds, which is roughly 33 bits.
If this guessing game ever takes place, I will be identified by the string `]@`. Having laid claim to this string first, I’ll obviously take precedence over anyone who tries to claim it later.
That’s 2 characters for me, which should put me ahead of everyone else on this site at the time of this post.
Suppose two beings are omniscient about Earth but not each other. One wants to point out one specific living human being on this planet to the other.
They must do this in the minimum number of ASCII characters such that they can be quite confident the other being will know exactly who they are referencing.
No previous common knowledge except common knowledge of the planet Earth and everything that can be logically deduced from that common knowledge.
Now suppose you pick a given person. How would you evaluate whether a proposed string has this property?
If they had a pre-agreed codebook, you’d need roughly log₂(8×10⁹) ≈ 33 bits ≈ 5 ASCII characters to index any human. If they are logically omniscient and omniscient about Earth, but do not have a pre-agreed codebook, how good can they get at minimax? How close to five chars?
If they can find a Schelling codebook they might be able to get the perfect 5 ascii chars for each person. But I’m not sure one exists. (perhaps birth time? encoded how?)
Even with a Schelling codebook, the 5 ascii char approach is dangerous because there are some 5-character strings that would suggest some other scheme is being used. For example, the guesser might have to assume the string
weiyiis referring to the Chinese chess player (the most prominent person with that name by far) and not a codebook entry.On the other hand, maybe being “logically omniscient,” the guesser would inevitably conclude that a codebook is the only reasonable scheme, and that would outweigh the enormous coincidence of the 5-character string so clearly identifying a person in English.
I don’t think this would be true because the string chooser picks a string after they know which person they are trying to point to
So, given that they need to point to Wei Yi, they might choose to use the name instead of the Schelling codebook if the Schelling codebook has a lower success probability than the name (even if the Schelling point is quite unique!). This is not a repeated game.
It’s hard to say what a UDT agent would do, though. It could go either way.
encoded how?
Via Unix time (milliseconds from Jan 1st 1970), and you can just trim whatever precision you don’t need. People are born with rate of 2/second, so you don’t need last 2 digits. Current timestamp is 10 digits long for seconds, which is roughly 33 bits.
You don’t encode the time directly. You sort all birth dates by time, and then encode the person’s rank in the sorted birth order.
You can’t just use timestamp because some people might be coincidentally born on the same millisecond.
A fun question is to think about what is the shortest string you can think of that would identify you. For me it’s the seven characters ‘satchlj’.
Xi and Ye have optimal names for this.
Upper bound for Americans might be USXXX-XX-XXXX
If this guessing game ever takes place, I will be identified by the string `]@`. Having laid claim to this string first, I’ll obviously take precedence over anyone who tries to claim it later.
That’s 2 characters for me, which should put me ahead of everyone else on this site at the time of this post.
Probably ’41haiku’ for me.
niplav