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LeanPool.Superdiffusion.Algsuperdiff.Section4.Provider.Schauder.CubeSchauderBoundaryZeroTrace

CubeSchauderBoundaryZeroTrace #

Ported from scottnarmstrong/Superdiffusion at 7f20476385d4af418f110303085ad0740c9eba46. Module imports, support namespace and local option directives adapted for Lean Pool.

Cube Schauder: the boundary zero-trace slot of the zero-datum competitor #

The boundary regime's classical-competitor producer carries one structural slot the interior regime does not have: the localized zero trace of the harmonic competitor v on the truncated window, tested against the reflected window. This is what licenses the odd reflection across the met faces.

For the zero-datum cube problem that slot is free. The competitor of CubeSchauderResidue.exists_frozenHarmonicReplacement_truncatedWindow is

  v = u|_{(x+□_k) ∩ □_m} − w ,   u ∈ H¹₀(□_m) ,   w ∈ H¹₀((x+□_k) ∩ □_m) ,

and both summands carry the trace: u by OneStepDatumZeroTrace.localizedZeroTraceFunctionOn_truncatedWindow_of_memH10_cube (a cutoff supported in the reflected window localizes the global zero trace on □_m to reflectedWindow ∩ □_m = (x+□_k) ∩ □_m), and w by localizedZeroTraceFunctionOn_of_memH10 because it is already H¹₀ of the window itself. The subtraction closure localizedZeroTraceFunctionOn_sub does the rest.

This module is that composition, stated pointwise on the value field so that it applies to any concrete realization of the difference (an H1Function subtraction, a restrict, or a hand-built carrier).

References #

The zero-datum boundary trace slot.

If u ∈ H¹₀(□_m) and v ∈ H¹₀((x+□_k) ∩ □_m), then their difference has the face-only localized zero trace on the truncated window against the reflected window. This is the zero-trace slot the boundary producer asks for, here at the frozen harmonic replacement of a zero-datum solution: no extra hypothesis is needed beyond the two memberships.