All proofs
Project-declaredLean 4.33.0-rc1 · mathlib@0434c033

Is Stable left limit

ProbabilityTheory.isStable_left_limit

Plain-language statement

The processes with left limits are a stable class.

Exact Lean statement

lemma isStable_left_limit :
    IsStable 𝓕 (fun (X : ι → Ω → E) ↦ ∀ ω, ∀ x, ∃ l, Tendsto (X · ω) (𝓝[<] x) (𝓝 l))

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
lemma isStable_left_limit :    IsStable 𝓕 (fun (X : ι  Ω  E)   ω,  x,  l, Tendsto (X · ω) (𝓝[<] x) (𝓝 l)) := by  refine isStable_pathwise (fun X i   l, Tendsto X (𝓝[<] i) (𝓝 l)) (fun i  ?_) ?_ ?_  · exact 0, tendsto_const_nhds  · intro X a hX i hai    cases lt_or_eq_of_le hai with    | inl hai =>      refine X a, ?_      have h_eq : (fun x  X (min x a)) =ᶠ[𝓝[<] i] fun _  X a := by        rw [eventuallyEq_nhdsWithin_iff]        filter_upwards [eventually_gt_nhds hai] with j haj        rw [min_eq_right haj.le]        grind      rw [tendsto_congr' h_eq]      exact tendsto_const_nhds    | inr hai =>      simp only [hai]      obtain l, hl := hX i      refine l, hl.congr' ?_      rw [eventuallyEq_nhdsWithin_iff]      filter_upwards [] with j hji      rw [min_eq_left]      grind  · intro X Y i hXY    have h_eq : X =ᶠ[𝓝[<] i] Y := by      rw [eventuallyEq_nhdsWithin_iff]      obtain k, hik, hk := hXY      filter_upwards [eventually_lt_nhds hik] with j hjk _      exact hk j hjk    constructor <;> rintro l, hl <;> refine l, hl.congr' ?_    · exact h_eq    · exact h_eq.symm
Project
Brownian motion
License
Apache-2.0
Commit
5077304f5e73
Source
BrownianMotion/StochasticIntegral/Locally.lean:198-229

Reuse this declaration

Bring the exact result into your workflow

The import identifies the source module. Your project still needs the pinned package dependency shown on this page.

What this badge means

This completion status comes from the project or community source. It has not yet been represented here as an independent rebuild and axiom audit.

Continue in this project

Related declarations

Project-declaredLean 4.33.0-rc1

Continuous Within At Iio indicator Ioc

continuousWithinAt_Iio_indicator_Ioc

Plain-language statement

The indicator of a half-open interval Ioc a b with constant value c is left-continuous: when approached from the left it is eventually constant, so it is continuous within Iio t at t for every t.

probabilitystochastic processesmeasure theory

Source project: Brownian motion

Person-level attribution pending.

View proof record
Project-declaredLean 4.33.0-rc1

Dense comap val nhds Within Ioi ne Bot

Dense.comap_val_nhdsWithin_Ioi_neBot

Project documentation

This is an auxillary lemma used to prove Dense.monotone_of_isRightContinuous. It is saying that if D is a dense set and a, b are two points such that a < b, then the comap of 𝓝[Set.Ioi a] a under the inclusion D → α is nontrivial. Note that a < b is necessary as this is clearly not true if a is a top element.

probabilitystochastic processesmeasure theory

Source project: Brownian motion

Person-level attribution pending.

View proof record