Heyting algebra Boolean algebra دیسهای 𝐵 = ⟨𝐴, ∧, ∨, -, 0, 1⟩𝐵 = ⟨𝐴, ∧, ∨, -, 0, 1⟩ 1.x ≼ x x ≼ x x ≼ xreflexiveaxiom▲ partially ordered set 2.(𝑥 ≼ 𝑦 𝑎𝑛𝑑 𝑦 ≼ 𝑥) ⇒ 𝑥=𝑦 (x ≼ y and y ≼ x) ⇒ x=y (x ≼ y and y ≼ x) ⇒ x=yantisymmetricaxiom▲ partially ordered set 3.(𝑥 ≼ 𝑦 𝑎𝑛𝑑 𝑦 ≼ 𝑧 ) ⇒ 𝑥 ≼ 𝑧 (x ≼ y and y ≼ z ) ⇒ x ≼ z (x ≼ y and y ≼ z ) ⇒ x ≼ ztransitiveaxiom▲ partially ordered set گسترشها Closure algebra