ii) CB objects may have subobjects which are not.
i) Consider the category generated by the graph
* * *
with the constraint that h o f = h o g, and the full
subcategory containing the two objects on the right.
h is not monic in the larger category, but -is- monic
in the subcategory, and so is k, yet the two objects
of the subcategory are not isomorphic.
ii) c*N + w*Z is CB in uStruct (any other object which
admits monomorphisms both ways clearly must have exactly
w copies of *Z, and exactly c many copies
of *N, and certainly no finite loops) and yet
*N + w*Z is not.