People can be added to the list. So 'other' is only if the right person is not added to the list by anyone at any point.

I take it the modal situation is Starmer wins in 2024 and serves (let's say) two terms as PM which takes us up to c.2033. Predicting that far out is going to be extremely difficult! I can't see any of the current crop of Tories being relevant at that point - on the contrary they are going to be deliberatlely looking for the kind of people nobody in 2022 had heard of (if Starmer loses his second election then maybe the next Tory PM might be someone we know.) Otherwise the only thing I can think of worth betting on would be someone we know in Labour taking over in a Brown/Blair kind of situation. Alternatively, if Sunak wins the next election (very unlikely imo), then it gets even harder to predict!

If Keir wins the next election, and then the election after, does this resolve as Keir, or are we talking the 2nd unique person to be PM after Rishi?

Has to be unique. Starmer then Starmer doesn't count.

then why is it offered as an option?

@3d the market was created in 2023, before it was certain that Starmer would be Sunak's successor. If there had been a Tory leadership challenge, Sunak's successor could've been, say, Badenoch, and then when she lost the election, this market would've resolved Starmer.

one argument is that - if starmer is competing on the next elections, and wins, and gets elected for another mandate, it would be still unique, since starmer from 2024 and starmer from 2028 would not be the same ...
second argument is - if it became impossible for starmer to be resolved to yes in the meantime because this situation was not anticipated at the time of creation of the market, it would be prudent to resolve it to NA ....

First argument, some people define identity that way but most don't, and the market creator explicitly didn't.

Second argument, it's not that we're in a situation that wasn't anticipated, it's just that we're in a situation that wasn't 100% certain. Lots of linked multiple choice markets have a value whose real probability goes to zero sometime after market creation and before resolution. NA would be absurd and would punish people who correctly predicted that Sunak wouldn't be replaced as Tory leader before the election.

and 3rd argument refers to this > "the market was created in 2023, before it was certain that Starmer would be Sunak's successor" AND "Has to be unique. Starmer then Starmer doesn't count." (clarified only 25 days ago, while my bet was 68 days ago, and there are other in the same situation)

If the author of the question says that it was completely certain that starmer would be sunak's successor, then it would have been correct to resolve the option "Keir Starmer" to "NA" at the point when author's certainty is "certain", because this criterion is mentioned/clarified 26 days ago, while the option was offered from the start ... it would be great if all of the users in this situation (which was not clarified beforehand) do not lose mana due to such unclaritiy ...
cheers

In a linked multiple-choice market like this one, you can't NA individual answers. It's the whole market or nothing.

Your bet 68 days ago was before the general election. The Conservatives could have won that election. Sunak could have resigned in 2027, been succeeded by Badenoch, who could have lost the next election in 2028 or so to Starmer. When you made your bet it was perfectly possible (although very unlikely) for the market to resolve Starmer. The only point at which it became literally impossible for the market to resolve Starmer was when Labour won the 2024 election. (and the clarification came basically that day)

I don't think the market was unclear. If I ask you "who was the prime minister after Tony Blair?" you're going to say "Gordon Brown", not "aha, trick question, Tony Blair again!" If you were hoping the market would resolve based on a pedantic gotcha like that, you should have clarified before making your bet.

Markets are always a little bit ambiguous. Creators should do their best to make everything clear, but if they miss something it's up to us as market participants to seek clarification, before placing bets we might regret.

You do mean after Sunak's successor right? So the PM after the next PM who themselves is after Sunak?

@ArtaxerxesTripp Yes, the PM after the PM after Sunak. In the US they conveniently refer to people as (for instance) 'the 49th President' but we don't seem to have a widely recognisable equivalent.