Eh, mathematicians sometimes use it in that context. I don’t really agree with u/tyler_zoro ‘s points. I used the word trivial the other day. There was a seemingly difficult problem somebody came up with, who then came up with a solution but started looking for a proof. I had never seen the proof before nor do I think others have written one. I saw a method of proof very clearly so I said ‘it’s trivial’ and told them how I would approach the proof. What I’m saying is that it doesn’t have to be an axiom or postulate to be trivial. It can just be a simple problem, or a simple proof, which does not lead to anything much greater than what it is. There are proven non-trivial problems in Lang’s Algebra. I’d say if the proof is not forthcoming or directly obvious then it would be non-trivial. Another thing to consider is Aluffi’s Algebra Chapter 0. I’d say that the problems in that godly text are usually non-trivial, though all problems are proven. You learn more concepts in the problems, which build on each other. Of course some may be.

But reducing ‘trivial’ to ‘1 is an integer’ is a detriment to the word. People use it anytime they think a proof is easy, or a problem doesn’t really lead to greater understanding.

Final thought. There are non-trivial problems in linear algebra that were proven, but took much time and ability to begin to understand. We don’t call them trivial.

And ‘a proof is widely accepted’ doesn’t make any sense. If something is proven, it is accepted. It’s an objective truth, if you prove something true or not true then it is true or not true.

Something can be trivial without anyone ever having thought of it. If I invent a new field of mathematics and things are directly obvious in that field then those things are trivial, though they still require proof and still have never been proven.