Natural continuity and integrability of actual matrix pairings.
theorem
AVenhance.Infra.Section4.iterate_matrix_pairing_continuousOn
{a b : AmnrSpace → Homogenization.Vec 2}
{A : AmnrSpace → Matrix (Fin 2) (Fin 2) ℝ}
{S : Set AmnrSpace}
(ha : ContinuousOn a S)
(hb : ContinuousOn b S)
(hA : ContinuousOn A S)
:
ContinuousOn (fun (z : AmnrSpace) => Homogenization.vecDot (a z) ((A z).mulVec (b z))) S
Actual vector and matrix continuity give joint pairing continuity.
theorem
AVenhance.Infra.Section4.iterate_matrix_pairing_integrable
{a b : AmnrSpace → Homogenization.Vec 2}
{A : AmnrSpace → Matrix (Fin 2) (Fin 2) ℝ}
(ha : ContinuousOn a (Set.Ici 0 ×ˢ Set.univ))
(hb : ContinuousOn b (Set.Ici 0 ×ˢ Set.univ))
(hA : ContinuousOn A (Set.Ici 0 ×ˢ Set.univ))
:
MeasureTheory.IntegrableOn (fun (z : AmnrSpace) => Homogenization.vecDot (a z) ((A z).mulVec (b z))) timeCube
MeasureTheory.volume
Natural timeCube integrability requires no quantitative pairing bound.