Talk:Representation theorem

This seems too restrictive
What about the Kolmogorov–Arnold representation theorem? I don't think we can see it in terms of isomorphism. What about the representation theorems in logic that show semantic equivalence? These send structures with one signature into structures with a different signature. So, we cannot have any isomorphism in these cases. I suspect that there are plenty of other examples of representation theorems that do not and cannot use the notion of isomorphism, which is very strong. --Dominic Mayers (talk) 19:59, 23 December 2018 (UTC)