So I’ve heard that a good thesis problem is one which will take you at least 5 years after you graduate to completely solve (or in the best case it is a problem which you will never solve completely, providing for a lifetime of work). Anyway, I’m getting close to “mostly solving” my original thesis problem: “Levi-flat hypersurfaces have Levi-flat singularities.” Of course it is only 3.5 years since I’ve finished my thesis so I’d better not completely solve it yet … That means I’ve been working on this sucker for over 5 years so far. That’s a reasonable problem. I think it’s got at least another few years in it before I’ve sucked it dry.
Then it amuses me when one of my students complains that a problem on the homework is hard because they’ve already
spent an hour on it and didn’t solve it yet.