B. Muckenhoupt posed in [1]
the problem of characterizing those non-negative functions u and v, which for some
p, 1 ≤ p < ∞, the inequality
holds for any f, where f denotes the Fourier transform of f. In this paper we deal
only with the case where either u ≡ 1 or v ≡ 1, finding that when v ≡ 1, 1 < p < 2, a
necessary condition is that for any r > 0,
where b = 2∕(2 − p), and that a sufficient condition (v ≡ 1,1 ≤ p) is that for any
measurable set E,
Similar conditions are obtained for the case u ≡ 1. Although we will show that the
sufficient condition is not necessary (in §4, Corollary 1 and again in §6, Corollary 3
and Remark 4), we were unable to obtain any conclusions on our necessary
condition.
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