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What are the guidelines? Will the moderators take action OR does someone have to flag it as "Known Unsolved Problem" or "Known Open Problem".
For instance question here was about a Diophantine Equation that is listed as Unsolved.
I think that an answer explaining that this is an open problem and perhaps listing a few sources for that (and maybe conjectures on the possible answers) should be a good step, no need to alert the moderators.