Tytuł pozycji:
On approach regions for the conjugate Poisson integral and singular integrals
Let ũ denote the conjugate Poisson integral of a function $f ∈ L^{p}(ℝ)$. We give conditions on a region Ω so that
$lim_{(v,ε)→(0,0)}_{(v,ε)∈Ω} ũ(x+v,ε) = Hf(x)$,
the Hilbert transform of f at x, for a.e. x. We also consider more general Calderón-Zygmund singular integrals and give conditions on a set Ω so that
$sup_{(v,r)∈Ω} |ʃ_{|t|>r} k(x+v-t)f(t)dt|$
is a bounded operator on $L^p$, 1 < p < ∞, and is weak (1,1).