Functional analysis is the mathematics of linear operators between vector spaces, so it's closely related to linear algebra, which is the mathematics of linear operators between finite-dimensional vector spaces. Linear algebra is therefore a subset of functional analysis. So maybe posts should go into the linear algebra forum? However, functional analysis is also a subset of analysis, and there is a calculus & analysis forum. So maybe that's where to post? Then there's the fact that proofs of theorems in functional analysis rely heavily on topology. When you study functional analysis, it feels more like topology than linear algebra or analysis. So maybe posts should go into the topology & geometry forum? People often post questions about functional analysis (about Hilbert spaces, unbounded operators, distribution theory) in the quantum physics forum too. Is that appropriate? I never report those posts to suggest a move, because I wouldn't know where to move them. I suggest that we change something to make it clear where posts about functional analysis should be. Perhaps break off the topology forum from the geometry & topology forum and create a topology & functional analysis forum. That would be a bit weird though, since (I think) stuff about algebraic topology is probably better off in the same forum as differential geometry. (Perhaps someone who actually understands algebraic topology will have something to say about that). Another option is to turn linear & abstract algebra into linear algebra and functional analysis. I think I like that better, but then the question is where to put abstract algebra. Now that I think about it, what about measure and integration theory? Is that set theory, or calculus/analysis? Maybe we should add a new forum called "measure theory & functional analysis" or something like that. An alternative to changing the names of the forums is to just change their descriptions. I don't know which option I like best, but I think we should discuss the options here.