claimroutineinferred_dep

Periodic cap estimate gives Euclidean pencil estimate

Removes periodicity: gives Euclidean pencil bound with [log⁡(2/h)]2/pc[\log(2/h)]^{2/p_c}
completes the pencil theorem by rescaling
Claim·§E.3 The fixed cap estimate·inside thmLocal smoothing for symmetric pencil waves

Statement (paper)

The Euclidean estimate holds for every b∈Cc∞(Γ)b\in C_c^\infty(\Gamma), 0<h≤10<h\le1 and Schwartz ff: finitely many caps cover the directions in supp⁡b\supp b, and the periodic (torus) estimate applied on the same lattice to C/MC/M and bM(η)=b(η/M)b_M(\eta)=b(\eta/M), with M≥1M\ge1 larger than sup⁡supp⁡b∣∇ϕ∣\sup_{\supp b}|\nabla\phi|, yields by the cube argument and rescaling fM(X)=f(MX)f_M(X)=f(MX) the bound ∥e−iTϕ(D)b(hD)f∥Lpc(Rn×[1,2])≤Cb[log⁡(2/h)]2/pc∥f∥Lpc(Rn)\|e^{-\mathrm iT\phi(D)}b(hD)f\|_{L^{p_c}(\RR^n\times[1,2])}\le C_b[\log(2/h)]^{2/p_c}\|f\|_{L^{p_c}(\RR^n)} for small hh, the remaining compact range of hh follows from smooth multiplier estimates, and the assertion for a simple smallest eigenvalue with negative definite transverse Hessian follows by applying the result to −C-C with cutoff bˉ\bar b and conjugating with f(X)↦f(−X)‾f(X)\mapsto\overline{f(-X)}.

In plain English

The Euclidean estimate ∥e−iTϕ(D)b(hD)f∥Lpc(Rn×[1,2])≤Cb[log⁡(2/h)]2/pc∥f∥Lpc\|e^{-\mathrm iT\phi(D)}b(hD)f\|_{L^{p_c}(\RR^n\times[1,2])}\le C_b[\log(2/h)]^{2/p_c}\|f\|_{L^{p_c}} holds for every b∈Cc∞(Γ)b\in C_c^\infty(\Gamma), 0<h≤10<h\le1 and Schwartz ff, and also for a simple smallest eigenvalue with negative definite transverse Hessian.

Why it's here

This step removes the periodicity assumption: the torus cap estimate from the previous claim is applied to rescaled data C/MC/M, bMb_M, and then transferred to Rn\RR^n by the cube argument and rescaling, with finitely many caps covering supp⁡b\supp b. Large hh is handled by smooth multiplier bounds, and the smallest-eigenvalue case follows by passing to −C-C and conjugating. This completes the proof of the pencil theorem, which the paper uses to obtain the main annulus estimate with its logarithmic loss.
Classified routine:
Transfers the torus cap estimate of the previous claim to Euclidean space by rescaling and a standard periodization (cube) argument. It then covers supp b\mathrm{supp}\, b by finitely many caps, handles the compact hh-range with smooth multiplier bounds, and treats the other eigenvalue case by conjugation symmetry.

Sources

PaperOpen
Section
§E.3 The fixed cap estimate
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sections/pencil.tex:283
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Friction

  • info
    inferred_dep
    outline: "Remove period by scaling; smallest eigenvalue case" rests on claim-thm-pencil-6
  • info
    inferred_dep
    outline: "Remove period by scaling; smallest eigenvalue case" rests on thm:main