Please identify the following:

[D R Brubaker]

Please be advised, I am not a teacher. I apologize for not knowing all of the ins and outs of this site. I am seeking an answer to what I believe is an incorrect usage issue. Is there a term for this type of statement: John and Thomas, they work together. Or, Michael Phelps, he is one of a kind. Is this or was this ever known as a double possessive? If anyone can identify the actual term for this I would greatly appreciate a response. Thank you.

[David L.]

I'm intrigued. Why is this a case of 'double possessives' as opposed to a punctuation issue?

As I understand double possessives:
Do we say "a friend of my uncle" or "a friend of my uncle's"? We distinguishing between "a picture of my father" (in which we see the father painted in all his glory) and "a picture of my father's" (a picture that the father owns).
I can't see how a construction such as "St. Paul's Cathedral's vergers" (whether a construction approved of or not) compares to your example. And similarly, 'friends of my sister' or 'my sister’s friends'

Where are we miles apart on this?

[D R Brubaker]

You have missed the point completely. The question is NOT what is a double possessive. I am looking for identification of the example I posted. Apparently I was told it was a double possessive INCORRECTLY. I want the answer to my original question. There should be no distance apart whatsoever.

[Anglika]

I cannot see that there is any possessive involved in your examples. Whoever told you this seems to have a curious idea of what possessive means.

[poorboy_9]

D R, I'm not sure the of the terminology (big help, right!), but without the "pre comma" proper noun(s), the prepositions wouldn't refer to anything. Perhaps it's like a "contraction" of two sentences: << John and Thomas are two men I know. They work together.>> would become: <<John and Thomas, they work together.>>
The only "posessive" context I can glen is that of existing-posessing an existence.
I hope this didn't send you off on a tangent!
B.
ps-please bear with D.L.-he's good, but a little long winded.

[Raymott]

Please be advised, I am not a teacher. I apologize for not knowing all of the ins and outs of this site. I am seeking an answer to what I believe is an incorrect usage issue. Is there a term for this type of statement: John and Thomas, they work together. Or, Michael Phelps, he is one of a kind. Is this or was this ever known as a double possessive? If anyone can identify the actual term for this I would greatly appreciate a response. Thank you.

This is usually called “subject repetition”
Here are some examples from the web:
“She noted a number of rules of usage that are shared by West African languages and Black Vernacular English, including the repetition of noun subject with pronoun: “my father, he work there”.
"My boss he is very rich"... do you speak like this? It is called the repeated subject error... “
“My computer, he don’t work. --> My computer won’t work. (human pronoun, subject repetition)