[awesomeMilou]

I'm curious since I'm not a mathematician: What do you mean by "stuck for a couple of weeks"? I am trying to practice more advanced math and have stumbled over lean and such but I can't imagine you just sit around for weeks to ponder over a problem, right? What do you do all this time?

[oggy]

I'm not a mathematician either ;) Yeah, I won't sit around and ponder at a property definition for weeks. But I will maybe spend a day on it, not get anywhere, and then spend an hour or two a day thinking about ways to formulate it. Sometimes I try something, then an hour later figure out it won't work, but sometimes I really do just stare at the ceiling with no idea how to proceed. Helps if you have someone to talk to about it!

[namibj]

Experience counter examples for why a specific definition is not going to work. Many times, at various levels of "not going to", usually hovering slightly above a syntactic level, but sometimes hovering on average above a plain definition semantic level, i.e. being mostly concerned with some indirect interaction aspects.