unital ring homomorphisms as subcategory of the category of non-unital rings
unital ring homomorphisms as subcategory of the category of non-unital rings

AV's mathbox only:
* auxiliary theorems for magam/monoid/rng/ring homomorphisms
* the set of unital ring homomorphisms is a "subcategory" of the category of non-unital rings.: ~rhmsubc

metamath/set.mm,metamath/set.mm,metamath/set.mm