What's the difference between
- A morphism with codomain $X$
- A generalized element of $X$
- A bundle over $X$?
They all seem to refer to a morphism with codomain $X$, but the different words are used in different situations.
What's the difference between
They all seem to refer to a morphism with codomain $X$, but the different words are used in different situations.
Yes, there is no formal difference. It happens frequently in category theory that objects which seem distinct, once sufficiently generalized, turn out to be special cases of the same general concept. A morphism $f:A\to X$ may also be thought of as a generalized element of $X$, indexed by or shaped like $A$, as if $A=S^1$ in a category of topological spaced, $f$ corresponds to a circle drawn in $X$. But $f$ may also be thought of as a bundle over $X$, especially if there is some nice notion of fiber in the given category and the fibers are nicely related.