Swift version 4.1 (swift-4.1-RELEASE)

2:37 AM

H(S^3; 𝐙) = { 0 : 𝐙, [v₄], 1 : 0, [], 2 : 0, [], 3 : 𝐙, [-1(v₀, v₁, v₃, v₄) + -1(v₁, v₂, v₃, v₄) + (v₀, v₁, v₂, v₄) + -1(v₀, v₁, v₂, v₃) + (v₀, v₂, v₃, v₄)] }