... by ω W1,p , l,wα ω W1,p , l,wα diam Ω −1 ω p ,Ω, wα ω p ,Ω, wα , 1.6where α is a real number.We denote the exterior derivative by d : D , l ... Lipk , l for loc Lipk , l,wα. Similarly, for u ∈ L1loc , l,wα , l 0, 1, ,n, we write u ∈ BMO , l,wα ifu , ,wα supσQ Ω μQ−1u − uQ1,Q,wα< ... theusual Lipschitz space with exponent k and write uLipk , for this norm. Similarly, for u ∈L1loc , l , l 0, 1, ,n, we write u ∈ BMO , l ifu , supσQ Ω |Q|−1u...