In three dimensions, the derivative has a special structure allowing the introduction of a cross product: ∇ ∇ F = ∇ ∇ ⋅ ⋅ F + ∇ ∇ ∧ ∧ F = ∇ ∇ ⋅ ⋅ F + I ∇ ∇ × × F from which it is easily seen that Gauss's law is the scalar part, the Ampère–Maxwell law is the vector part, Faraday's law is the pseudovector part, and Gauss's law for magnetism is the pseudoscalar part of the equation. After expanding and rearranging, this can be written as ( ∇ ∇ ⋅ ⋅ E − − ρ ρ ε ε 0 ) − − c ( ∇ ∇ × × B − − μ μ 0 ε ε 0 ∂ ∂ E ∂ ∂ t − − μ μ 0 J ) + I ( ∇ ∇ × × E + ∂ ∂ B ∂ ∂ t ) + I c ( ∇ ∇ ⋅ ⋅ B ) = 0