I don't understand what the notation means.

For example when the author says:

P(Q ⊆ X | ∀ x ∈ Q (x = 1))

This is equivalent to P(Q ⊆ X | Q = {1}), which further simplifies to P(1∈X).

This seems to be a type error (isn't X supposed to be a set of binary variables?), and also an awfully cumbersome way to write P(1∈X).

Anyone have some idea what the article is trying to say?