“…2. An (r 0 , s 1 )-fuzzy 𝛼-open set ((r 0 , s 1 )-f𝛼-open, for short) [8], if λ 1 ≤ 𝐼 𝜏,𝜏 * (𝐶 𝜏,𝜏 * (λ 1 , r 0 , s 1 ), r 0 , s 1 )) and an (r 0 , s 1 )-fuzzy 𝛼-closed set ((r 0 , s 1 )-f𝛼-closed, for short), if 𝐶 𝜏,𝜏 * (𝐼 𝜏,𝜏 * (𝐶 𝜏, 𝜏 * (λ 1 ,r 0 , s 1 ), r 0 , s 1 )) ≤ λ 1 ,.…”