Theorem

minimal postulates for a field 𝒜\mathcal{A}

  1. Ω∈𝒜\Omega \in \mathcal{A}
  2. A∈𝒜⟹A∁∈𝒜A \in \mathcal{A} \implies A^{\complement} \in \mathcal{A}
  3. A,B∈𝒜⟹A∪B∈𝒜A, B \in \mathcal{A} \implies A \cup B \in \mathcal{A}