Also, with composition, Phil Hirschhorn does something quite lovely in his book Model Categories and their localizations. Instead of writing composites with by any convention in particular, he just writes composites literally as their composites $A\to B\to C$ with the name of the arrow above the arrow.
]]>For background, the question was closed as "doesn't belong here".
Now, one could make a case pro or contra having questions like that on Math Overflow (I have no opinion on this matter, and I'm not interested on wasting everyone's time discussing this) but I certainly think people should learn about changes in policy.
I'm not going to say anything about how exactly moderators should close the questions -- it's one of the points of having competent moderators that they're more often right than not -- but it's probably best to communicate somewhere what happens. Otherwise, moderators' time will be wasted on explaining on many similar questions the reasons for closing that could be explained only once.
For example, for many "What is..." questions, a reference to nLab would be more than sufficient to close the question, without entering hard and long discussions (of which you might have seen an example here). Surely, there could be other cases of "speedy close" (modeled after "speedy delete") questions, that would be dealt with fast and efficient.
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