摘 要: | Let Q_0 be a Cube in R~n and u(x)∈L~p(Q_0).Suppose that∫_Q丨u(x t)-u(x)丨~pdx≤K~p丨t丨~(ap)丨Q丨~(1/β/n)for all parallel subcubes Q in Q_0 and for all t such that the integral makes sense with K≥0,0<α≤1, 0≤β≤n and p≥1.If αp=β,then u(x)is of bounded mean oscillation on Q_0(abbreviated to BMO(Q_0)),i.e.sup QQ_0 1/丨Q丨∫_Q丨u(x)-u_Q丨dx=‖u‖<∞,where u_Q is the mean value of u(x)over Q.
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