👉 In mathematical logic, the term "antiposition" refers to a logical statement that asserts that the negation of an existential quantifier (e.g., ∀x P(x)) is equivalent to the negation of the negation of the universal quantifier (¬∀x P(x)). This is often used in proof theory and model theory, where it serves as a way to formalize the concept of "not only exists but also belongs" or "not only belongs but also exists."
