A few weeks ago, I submitted a mathematical paper in which the main proof contains a sentence that says: “by X and by Y, then Z is true”. It turns out that, luckily, the sentence is true. However, it is not nearly as direct as I am claiming in my paper. I have now been able to develop the argument by which for X and Y, Z is true; and it turns out that it is a half-page long argument.
Beyond never revising already submitted papers, is there anything I can do about it? Should I perhaps notify the editor-in-charge?