Documentation

Mathlib.Geometry.Manifold.IntegralCurve.Transform

Translation and scaling of integral curves #

New integral curves may be constructed by translating or scaling the domain of an existing integral curve.

Reference #

Tags #

integral curve, vector field

Translation lemmas #

theorem IsIntegralCurveOn.comp_add {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {s : Set ℝ} (hγ : IsIntegralCurveOn γ v s) (dt : ℝ) :
IsIntegralCurveOn (γ ∘ fun (x : ℝ) => x + dt) v (-dt +ᵥ s)
theorem isIntegralCurveOn_comp_add {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {s : Set ℝ} {dt : ℝ} :
IsIntegralCurveOn γ v s ↔ IsIntegralCurveOn (γ ∘ fun (x : ℝ) => x + dt) v (-dt +ᵥ s)
theorem isIntegralCurveOn_comp_sub {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {s : Set ℝ} {dt : ℝ} :
IsIntegralCurveOn γ v s ↔ IsIntegralCurveOn (γ ∘ fun (x : ℝ) => x - dt) v (dt +ᵥ s)
theorem IsIntegralCurveAt.comp_add {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {t₀ : ℝ} (hγ : IsIntegralCurveAt γ v t₀) (dt : ℝ) :
IsIntegralCurveAt (γ ∘ fun (x : ℝ) => x + dt) v (t₀ - dt)
theorem isIntegralCurveAt_comp_add {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {t₀ dt : ℝ} :
IsIntegralCurveAt γ v t₀ ↔ IsIntegralCurveAt (γ ∘ fun (x : ℝ) => x + dt) v (t₀ - dt)
theorem isIntegralCurveAt_comp_sub {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {t₀ dt : ℝ} :
IsIntegralCurveAt γ v t₀ ↔ IsIntegralCurveAt (γ ∘ fun (x : ℝ) => x - dt) v (t₀ + dt)
theorem IsIntegralCurve.comp_add {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} (hγ : IsIntegralCurve γ v) (dt : ℝ) :
IsIntegralCurve (γ ∘ fun (x : ℝ) => x + dt) v
theorem isIntegralCurve_comp_add {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {dt : ℝ} :
IsIntegralCurve γ v ↔ IsIntegralCurve (γ ∘ fun (x : ℝ) => x + dt) v
theorem isIntegralCurve_comp_sub {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {dt : ℝ} :
IsIntegralCurve γ v ↔ IsIntegralCurve (γ ∘ fun (x : ℝ) => x - dt) v

Scaling lemmas #

theorem IsIntegralCurveOn.comp_mul {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {s : Set ℝ} (hγ : IsIntegralCurveOn γ v s) (a : ℝ) :
IsIntegralCurveOn (γ ∘ fun (x : ℝ) => x * a) (a • v) {t : ℝ | t * a ∈ s}
theorem isIntegralCurveOn_comp_mul_ne_zero {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {s : Set ℝ} {a : ℝ} (ha : a ≠ 0) :
IsIntegralCurveOn γ v s ↔ IsIntegralCurveOn (γ ∘ fun (x : ℝ) => x * a) (a • v) {t : ℝ | t * a ∈ s}
theorem IsIntegralCurveAt.comp_mul_ne_zero {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {t₀ : ℝ} (hγ : IsIntegralCurveAt γ v t₀) {a : ℝ} (ha : a ≠ 0) :
IsIntegralCurveAt (γ ∘ fun (x : ℝ) => x * a) (a • v) (t₀ / a)
theorem isIntegralCurveAt_comp_mul_ne_zero {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {t₀ a : ℝ} (ha : a ≠ 0) :
IsIntegralCurveAt γ v t₀ ↔ IsIntegralCurveAt (γ ∘ fun (x : ℝ) => x * a) (a • v) (t₀ / a)
theorem IsIntegralCurve.comp_mul {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} (hγ : IsIntegralCurve γ v) (a : ℝ) :
IsIntegralCurve (γ ∘ fun (x : ℝ) => x * a) (a • v)
theorem isIntegralCurve_comp_mul_ne_zero {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {γ : ℝ → M} {v : (x : M) → TangentSpace I x} {a : ℝ} (ha : a ≠ 0) :
IsIntegralCurve γ v ↔ IsIntegralCurve (γ ∘ fun (x : ℝ) => x * a) (a • v)
theorem isIntegralCurve_const {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {H : Type u_2} [TopologicalSpace H] {I : ModelWithCorners ℝ E H} {M : Type u_3} [TopologicalSpace M] [ChartedSpace H M] {v : (x : M) → TangentSpace I x} {x : M} (h : v x = 0) :
IsIntegralCurve (fun (x_1 : ℝ) => x) v

If the vector field v vanishes at x₀, then the constant curve at x₀ is a global integral curve of v.