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Scott Spencer

Publications and source records attributed to Scott Spencer.

6 recordsLinked to original sources
arXiv2017

Sparse Bounds for Oscillatory and Random Singular Integrals

Let $ T_{P } f (x) = \int e ^{i P (y)} K (y) f (x-y) \; dy $, where $ K (y)$ is a smooth Calderón-Zygmund kernel on $ \mathbb R ^{n}$, and $ P$ be a polynomial. We show that there is a sparse bound for the bilinear form $ \langle T_P f, g \rangle$. This in turn easily implies $ A_p $ inequalities. The method of proof is applied in a random discrete setting, yielding the first weighted inequalities for operators defined on sparse sets of integers.

math.CA↗
arXiv2016

Noisy 1-Bit Compressed Sensing Embeddings Enjoy a Restricted Isometry Property

We investigate the sign-linear embeddings of 1-bit compressed sensing given by Gaussian measurements. One can give short arguments concerning a Restricted Isometry Property of such maps using Vapnik-Chervonenkis dimension of sparse hemispheres. This approach has a natural extension to the presence of additive white noise prior to quantization. Noisy one-bit mappings are shown to satisfy an RIP when the metric on the sphere is given by the noise.

math.CA↗
arXiv2015

Two-Weight Inequalities for Commutators with Fractional Integral Operators

In this paper we investigate weighted norm inequalities for the commutator of a fractional integral operator and multiplication by a function. In particular, we show that, for $μ,λ\in A_{p,q}$ and $α/n+1/q=1/p$, the norm $\| [b,I_α]:L^p(μ^p)\to L^q(λ^q) \|$ is equivalent to the norm of $b$ in the weighted BMO space $BMO(ν)$, where $ν=μλ^{-1}$. This work extends some of the results on this topic existing in the literature, and continues a line of investigation which was initiated by Bloom in 1985 and was recently developed further by the first author, Lacey, and Wick.

math.CA↗
arXiv2015

On Entropy Bumps for Calderón-Zygmund Operators

We study two weight inequalities in the recent innovative language of `entropy' due to Treil-Volberg. The inequalities are extended to $ L ^{p}$, for $ 1< p \neq 2 < \infty $, with new short proofs. A result proved is as follows. Let $ \varepsilon $ be a monotonic increasing function on $ (1, \infty)$ which satisfy $ \int _{1} ^{\infty} \frac {dt} {\varepsilon (t) t} = 1$. Let $ σ$ and $ w$ be two weights on $ \mathbb R ^{d}$. If this supremum is finite, for a choice of $ 1< p < \infty $, $$ \sup _{Q} \biggl[ \frac {σ(Q)} {\lvert Q\rvert} \biggr]^{p-1} \frac {\int _{Q} M (σχ_{Q})} {σ(Q)} \cdot \frac {w (Q)} {\lvert Q\rvert}\biggl[ \frac {\int _{Q} M (w χ_{Q})} {w (Q)}\biggr]^{p-1} < \infty, $$ then any Calderón-Zygmund operator $ T$ satisfies the bound $ \lVert T _σ f \rVert _{L ^{p} (w)} \lesssim \lVert f\rVert _{L ^{p} (σ)} $.

math.CA↗
arXiv2015

Some Entropy Bump Conditions for Fractional Maximal and Integral Operators

We investigate weighted inequalities for fractional maximal operators and fractional integral operators. We work within the innovative framework of "entropy bounds" introduced by Treil--Volberg. Using techniques developed by Lacey and the second author, we are able to efficiently prove the weighted inequalities.

math.CA↗