[#束論](束論) [#Lattice_Theory](Lattice_Theory) [https://en.wikipedia.org/wiki/Semilattice](https://en.wikipedia.org/wiki/Semilattice) [https://ja.wikipedia.org/wiki/結びと交わり](https://ja.wikipedia.org/wiki/結びと交わり) - Idempotent Law (冪等性): $a \vee a = a$ - Associative Law (結合性): $a \vee (b \vee c) = (a \vee b) \vee c$ - Commutative Law (可換性): $a \vee b = b \vee a$