OAI/Analysis/Nonexpansive/AdaptiveRun.lean

GitHub source file

2 declarations, 0 contain sorry, 0 declared as axioms

Successive choices with arbitrary auxiliary state

The state may contain the entire preceding candidate history. A threshold is read before the next map is selected; the transition relation supplies auxiliary choices only after that map is known. No convex coefficients are involved in this infinite sequence.

  1. theorem OAI.ReflexiveFixedPoints.exists_adaptive_metric_run line 29

    Source documentation

    A legal infinite sequence exists even when every threshold and every legal auxiliary transition depends on the whole preceding state. The caller may take the state to be a list of all previous candidate records.

    theorem exists_adaptive_metric_run
        {S : Type u} {M : Type v} {W : Type w} [PseudoMetricSpace W]
        {q : ℕ} (hq : 0 < q) (target : Fin q → W)
        (eval : M → W) (family : ℕ → Set M)
        (threshold : ℕ → S → ℕ)
        (transition : ℕ → S → M → S → Prop) (initial : S)
        (hclosure : ∀ (i : ℕ) (s : S) (r : Fin q),
          target r ∈ closure (eval '' family (threshold i s)))
        (htransition : ∀ (i : ℕ) (s : S) (a : M),
          a ∈ family (threshold i s) → ∃ s', transition i s a s') :
        ∃ (state : ℕ → S) (selected : ℕ → M),
          state 0 = initial ∧ ∀ i,
    …
  2. theorem OAI.ReflexiveFixedPoints.tendsto_cyclic_target line 65

    Source documentation

    Cycling through finitely many targets with a vanishing error gives a convergent subsequence for each target. The selected maps and their state history are otherwise unrestricted.

    theorem tendsto_cyclic_target
        {W : Type w} [PseudoMetricSpace W] {q : ℕ} (hq : 0 < q)
        (target : Fin q → W) (u : ℕ → W)
        (hclose : ∀ i, dist (u i) (target ⟨i % q, Nat.mod_lt i hq⟩) <
          1 / ((i : ℝ) + 1)) (r : Fin q) :
        Tendsto (fun n : ℕ => u (q * n + r.val)) atTop (𝓝 (target r)) := by
    …