A compactly supported Weil correlation is unchanged by adding a tempered distribution whose distributional support lies outside its doubled window.
Theorem 1.1 (External support is invisible to local Weil correlations).
∀ L : Real ( ) , w e i lS o u rce , ka pp a : TemperedDistribution ( Real ( ) , Complex ( ) ) , hka pp a : dsupport ( ka pp a ) ⊆ compl ( Ioo ( − 2 L , 2 ⋅ L ) ) , f , h : Real ( ) → Complex ( ) , h f S m oo t h : ContDiff ( Real ( ) , infinity ( ) , f ) , hh S m oo t h : ContDiff ( Real ( ) , infinity ( ) , h ) , h f C o m p a c t : HasCompactSupport ( f ) , hh C o m p a c t : HasCompactSupport ( h ) , h f S u pp or t : tsupport ( f ) ⊆ Ioo ( − L , L ) , hh S u pp or t : tsupport ( h ) ⊆ Ioo ( − L , L ) ⇒ let corre l a t i o n := weilTest ( f , h ) , let h corre l a t i o n C o m p a c t : HasCompactSupport ( corre l a t i o n ) := weilTestHasCompactSupport ( h f C o m p a c t , hh C o m p a c t ) , let h corre l a t i o n S m oo t h : ContDiff ( Real ( ) , infinity ( ) , corre l a t i o n ) := contDiffConvolutionRight ( hasCompactSupportTilde ( hh C o m p a c t ) , h f S m oo t h , contDiffTilde ( hh S m oo t h ) ) , let corre l a t i o n T es t := toSchwartzMap ( corre l a t i o n , h corre l a t i o n C o m p a c t , h corre l a t i o n S m oo t h ) , add ( w e i lS o u rce , ka pp a ) ( corre l a t i o n T es t ) = w e i lS o u rce ( corre l a t i o n T es t ) .
Proof. Machine-checked in Lean as D5/S3/Weil/TestFunctions/ExternalSupportInvisibility.external_support_invisibility (✓ std3). ∎
Source. Repository-derived.
Commentary.
The canonical Weil correlation is constructed from the two supplied smooth compact tests. Its strict doubled-window support permits a finite smooth partition-of-unity decomposition into neighborhoods where the added tempered distribution vanishes.