Actual differential calculus of a single harmonic #
All directional operators below are evaluations of the Fréchet derivative.
The direction fields may vary with the point, so their derivatives are included
in the iterated operators. The cylindrical formulas use the unscaled angular
direction, with its factors of R⁻¹ and R⁻² displayed explicitly.
Exact differential calculus on the auxiliary graph #
The physical variables are (r,t) and the auxiliary variable is in ℝ².
The graph is Y(r,t) = r^d • vr + t • vt, as in Definition 8.1 of the
candidate manuscript. The radial formulas below are stated away from r = 0.
All differential operators use Mathlib's actual Fréchet derivatives.
Plane: an abbreviation for ℝ × ℝ.
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The radial coefficient in the exact graph derivative.
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- NavierStokes.GraphCalculus.radialSpeed d r = d * r ^ (d - 1)
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Pullback, defined pointwise by F (graph d vr vt q).
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- NavierStokes.GraphCalculus.pullback d vr vt F q = F (NavierStokes.GraphCalculus.graph d vr vt q)
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Radial vector, given by ((1, 0), radialSpeed d p.1.1 • vr).
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- NavierStokes.GraphCalculus.radialVector d vr p = ((1, 0), NavierStokes.GraphCalculus.radialSpeed d p.1.1 • vr)
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A general commutator identity when both cross derivatives of the vector
fields vanish. The regularity assumption is ordinary C² regularity.
The time direction has constant graph velocity.
First radial derivative of the physical pullback equals the exact graph operator.
The coordinate map is smooth to every order away from the axis.
The radial graph coefficient is independent of both time and the auxiliary coordinates. Its derivative in the time graph direction is zero.
The actual radial and time graph operators commute on every C² lift,
away from the radial axis. This proves the relevant assertion of §8.1.
Restriction to the graph preserves each differentiability order away
from the axis, in particular C∞ when the order is ∞.
A derivative in an auxiliary direction is the ordinary dot product with the two auxiliary partial derivatives.
The actual derivative in a prescribed, possibly varying direction field.
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- NavierStokes.HarmonicCalculus.along V f x = (fderiv ℝ f x) (V x)
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The imaginary frequency i κ.
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κ = k*j gives the carrier in the manuscript.
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A coefficient multiplied by one actual complex harmonic.
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- NavierStokes.HarmonicCalculus.mode κ Φ a x = a x * NavierStokes.HarmonicCalculus.carrier κ Φ x
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First product formula, with the phase derivative and the coefficient derivative separated.
Second product formula. Because the direction field is inside along,
its derivative is present in both along V (along V a) and the second phase
derivative; no constancy of the field is assumed.
Cylindrical scalar operators #
The scalar cylindrical Laplacian, also valid on prescribed graph
directions. Vθ is the unscaled angular direction.
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The actual phase gradient in the orthonormal cylindrical frame.
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The phase-square coefficient before rewriting it as a normal norm.
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The phase/coefficient cross term in the scalar Laplacian.
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Exact phase-square, cross, and phase-divergence decomposition.
Equivalent formulation using the squared Euclidean length of the actual normal.
An angular derivative which is constant near the point has zero next angular derivative. This applies to the affine angular phase and to angularly independent stripped coefficients.
With no angular coefficient dependence, its scalar Laplacian contains only radial and axial coefficient derivatives.
For an affine angular phase, the phase-divergence term is exactly
Dr n_r + n_r/R + Dz n_z.
The scalar part of the manuscript's no-slow-angular-dependence formula. Both the absent angular coefficient derivative and the affine angular phase are hypotheses on actual derivatives on an open set.
Divergence and the longitudinal gain #
Complex-bilinear contraction with a real normal.
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Vector mode, defined pointwise by mode κ Φ (fun y => a y i) x.
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- NavierStokes.HarmonicCalculus.vectorMode κ Φ a x i = NavierStokes.HarmonicCalculus.mode κ Φ (fun (y : E) => a y i) x
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The derivative of the cylindrical frame with respect to angle.
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The scalar component Laplacians plus the two cylindrical frame connections. Its identification with Cartesian vector Laplacian belongs to the cylindrical coordinate calculus.
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Harmonic vector Laplacian, including the additional angular frame
term 2 i κ (n_θ/R) J a. All coefficient and phase derivatives remain actual
directional Fréchet derivatives.
Angularly independent coefficients retain only the J² a/R²
connection, namely -(a_r,a_θ,0)/R².
Divergence of physical cylindrical components in prescribed directions.
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The divergence of a coefficient with no angular dependence.
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Exact harmonic divergence forces the longitudinal identity. The only
coefficient angular derivative used by divergence is that of a_θ.
The complex coefficient in the direction of the unit real normal.
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Exact divergence supplies the frequency gain; the identity is proved above from the actual harmonic derivative, not assumed here.
Quantitative pointwise gain using actual radial and axial derivatives of the coefficient.
A lower bound on radius and normal, together with bounds on the actual coefficient derivatives, yields the uniform inverse-frequency gain.
The manuscript frequency is κ = k*j, with a nonzero integer harmonic.
Operator norms of the actual full coefficient derivatives can be used to supply the directional derivative bounds above.
Finite jets of the longitudinal contraction #
At every derivative order, the contraction n·a has the same
inverse-frequency factor. Derivatives of the normal are included on the
left, and derivatives of the full coefficient divergence on the right.
Uniform finite-jet version of the exact contraction estimate.
The coefficient divergence bound is derived from actual coefficient
jets through order m+1, and graph-direction and inverse-radius jets
through order m.
Compatibility with the phase and graph already formalized #
This carrier is the previously formalized slot harmonic, including its integer-harmonic and angular-period conventions.
The graph direction in the axial slot is ε ∂Z; after that rescaling
the normal here is exactly the normal used in the phase module.
Restricting a complex harmonic to the actual auxiliary graph gives the radial product formula with the genuine radial graph vector field.
The analogous actual graph pullback identity in its time direction.