Upper Bound For a subset 𝑆 of field 𝐹, 𝑠̃∊𝐹 is called an upper bound of 𝑆 if: ∀𝑠∊𝑆: 𝑠≤𝑠̃ Lower Bound For a subset 𝑆 of field 𝐹, 𝑠̃∊𝐹 is called a lower bound of 𝑆 if: ∀𝑠∊𝑆: 𝑠≥𝑠̃