Elixir, no circular reference possible?

Question

I am learning Elixir, up to chapter 7 PragProg book, and after thinking about the immutability and other items, I was thinking it was not generally possible to create a circular reference in the Elixir Maps/Tuples/Lists, etc.. Where A -> B -> C -> A.

Without going into really trying to trick the system, is this true?

Answer 1

Due to the immutability, there is a chicken-egg problem creating circulars. In fact, there is nothing done by Elixir to prevent it; it just comes out of the box within the immutability.

Proof: Since C in your chain links A on creation, A must exist in advance; A in turn links B hence B must exist even before; B links C, requiring C to exist, but it is not yet created. QED.

One can not simply refer an unexisting Term^*, and can not modify the existing one, therefore, it is impossible in Elixir.

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* _{please read the discussion in comments on wording here and why Term was finally chosen.}