> Perhaps it isn't and it is a nice PR for beginners. By the way, there is a steady stream of people who come into the "new members" channel on the Lean zulip

> Perhaps it isn't and it is a nice PR for beginners. By the way, there is a steady stream of people who come into the "new members" channel on the Lean zulip and ask for ideas for a minor contribution they can make. The stock answer is generally that the low-hanging fruit has been picked. But that isn't really accurate. If your goal is to get something, anything, into mathlib with your name on it, you probably can. Choose some undergraduate exercises, try to formalize them using mathlib, and at some point you'll run into some convenience lemmas that you wish were present. You can then produce one of those lemmas and try to get it accepted. (As part of a project I'm working on, I produced a proof that involved showing that a function was bijective from the already-existing mathlib theorems that it was injective and surjective. There was no one-step existing theorem despite the existence of the injectivity and surjectivity theorems. When I complained about some other part of my proof, somebody else picked up on that and quickly submitted a convenience theorem directly stating the bijectivity. That's the kind of thing I'm talking about, though you can go more complex than that example.)