## Well-definedness on C∞0(Rn)C_{0}^{\infty}(\mathbb{R}^{n})

Let T be a Calderon-Zygmund operator associated to a Calderon-Zygmund kernel K∈CZKα of order α>0 and b∈BMO(Rn). Then for f∈C∞0(Rn) define[b,T](f)=b⋅Tf−T(bf). Question. Is [b,T] is well-defined on C∞0(Rn) for all b∈BMO(Rn)? Answer AttributionSource : Link , Question Author : Timothy , Answer Author : Community