Abstract Nonsense
en.wikipedia.orgI've found it difficult in writing information theoretic/statistics papers anticipating what is obvious or assumable and what is not. Things I think are obvious or established beyond doubt because they're so self evident become points of contention, and things that were not obvious to me at all are called out as common knowledge.
Relevant xkcd: https://xkcd.com/2501/
At least with information theory/statistics someone could write a moderately amusing paper about this, if the field has anything like what SIGBOVIK is for computation.
In programming we call that stuff boilerplate.
For me it's not the same notion. Imho a proof is by "abstract nonsense" when it is a relatively short sequence of seemingly uninteresting steps that end up proving something non-trivial in the end. And you're left wondering how this stupid symbolic manipulations which looked just like a sequence of reformulations of the initial thing could have possibly proved the statement. This appears a lot in category theory because the manipulated objects are very rich and usually there are a lot of different ways to describe the same thing. Hence you can sometimes just dive into such abstract tunnels and end up at a quite different location giving other insights.
Boilerplate in proofs is usually what we call "administrative arguments".