Constructive decomposition of functions of finite central mean oscillation

The space CMO of functions of finite central mean oscillation is an analogu e of BMO where the condition that the sharp maximal function is bounded is replaced by the convergence of the sharp function at the origin. In this pa per it is shown that each element of CMO is a singular integral image of an element of the Beurling space B-2 of functions whose Hardy-Littlewood maxi mal function converges at zero. This result is an analogue of Uchiyama's co nstructive decomposition of BMO in terms of singular integral images of bou nded functions. The argument shows, in fact, that to each element of CMO on e can construct a vector Calderon-Zygmund operator that maps that element i nto the proper subspace B-2.