I have a question about general Arbital practice here. A mathematician will probably already know what a group homomorphism is, but they probably also don't need the proofs of the Properties, for instance, and they don't need the explanation of the trivial group. Should I have split this up into different lenses in some way?
so8res: "I would set up the page as follows:
A group homomorphism is X. Key properties of group homomorphisms include:
1. Thing. Implications implications implications. (Proof.)
2. Thing. Implications implications. (Proof.)
...
I'd then eventually add an intro lens."
Having proofs on child pages makes sense to me too.