You have
L = L0
Yes separately they could be the base case (tail) for a difference list, e.g.
L.
L0.
I don’t know what you are implying with the unification, e.g.
L = L0.
EDIT
Three ways I use to check if something is a difference list
1). Look at the examples in these test cases and do a mental comparison. Note: Because Discourse doesn’t have an easy way to add an HTML anchor to an expandable section you will have to click on the triangle to see the test cases.
2). Use the Prolog code that checks if a pair is a difference list. Note: Because Discourse doesn’t have an easy way to add an HTML anchor to an expandable section you will have to click on the triangle to see the code.
3). Use write_term/2 with the option dotlists(true) as done in the earlier post and do a mental comparison.