Re: #9 John
1. What is the difference between an element and an object?

Re: #5 John
2. Are all morphisms in a category of the same type or can a category have, for example, objects {\$$x,y,a,b\$$} where morphisms \$$f: x \rightarrow y\$$ and \$$g: a \rightarrow b\$$ are different?

Thanks!