Databases - Relational Calculus

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    Here is my stab at the logic, derived from giyam's answers below and Googling set notation:

    Give me the set of x such that for all y in set(x) and set(y) is a function of (where) y <= x

    However, I think the italicized section above is unclear due to the nature of the problem as it is written...that is, what is the relationship with y and 'S(x)' after ∀?

    Definitions:

    ∀ = forall (https://en.wikipedia.org/wiki/Turned_A)

    | = such that (https://en.wikipedia.org/wiki/Set-builder_notation)

    ∧ = logical conjunction (and)(https://en.wikipedia.org/wiki/List_of_logic_symbols)

    → = is a function from(https://math.stackexchange.com/questions/1740154/different-arrows-in-set-theory-rightarrow-and-mapsto)