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ComplementedSubspace/TheoremStatement.lean

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1import ComplementedSubspace.AmbientSeparable
2import ComplementedSubspace.LocalUnconditional
3import Mathlib.Analysis.Convex.Uniform
4import Mathlib.Analysis.Normed.Order.Lattice
5import Mathlib.Algebra.Order.Module.Defs
6
7/-!
8# The precise real main-theorem statement
9
10`RealMainTheoremStatement` is a proposition, not a theorem declaration or an
11axiom. Its proof is `realMainTheorem` in `RealMainTheorem.lean`.
12Its parameters and four range/dual conclusions are those of the main
13theorem in `1-Introduction.tex` of the supplied manuscript.
14
15The target asks for uniform convexity in the inherited ambient norm, a stronger
16property proved in the manuscript's construction. The analytic implication to
17superreflexivity has not been formalized here, and no such implication is
18assumed. In particular, this file does not confuse Banach-space reflexivity
19with the algebraic notion of module reflexivity.
20
21The lattice-order predicate below has its actual mathematical definition. It
22preserves the existing normed real vector space and its complete metric; only
23the compatible lattice order is existentially quantified.
24-/
25
26noncomputable section
27
28open scoped NNReal ENNReal Topology
29
30namespace ComplementedSubspace
31
32/-- A compatible real Banach lattice order on an existing real Banach space.
33The norm and scalar multiplication remain the inherited ones. -/
34def HasRealBanachLatticeOrder (X : Type*) [NormedAddCommGroup X]
35 [NormedSpace ℝ X] [CompleteSpace X] : Prop :=
36 ∃ latticeOrder : Lattice X,
37 letI : Lattice X := latticeOrder
38 IsOrderedAddMonoid X ∧ PosSMulMono ℝ X ∧ HasSolidNorm X
39
40/-- The two quantitative local-structure assertions for a projection range
41and its continuous dual, with their inherited and operator norms. -/
42def HasSeparatedRange {X : Type*} [NormedAddCommGroup X] [NormedSpace ℝ X]
43 (P : X →L[ℝ] X) : Prop :=
44 chiGL ↥P.range ≤ ‖P‖ₑ ∧
45 chiDPR ↥P.range = ⊤ ∧
46 chiGL (↥P.range →L[ℝ] ℝ) ≤ ‖P‖ₑ ∧
47 chiDPR (↥P.range →L[ℝ] ℝ) = ⊤
48
49/-- The real main-theorem target, with the stronger uniform-convexity property
50of the constructed ambient space. Proved in `RealMainTheorem.lean`.
51
52`BlockParameters` records positive dimensions, exponents in `(2,3]`, monotone
53decrease, and convergence to two. `Ambient` is the actual dependent counting-
54norm `ℓ²` sum of those finite `ℓᵖ` blocks. -/
55def RealMainTheoremStatement : Prop :=
56 ∀ ρ : ℝ, 0 < ρ →
57 ∃ a : BlockParameters,
58 TopologicalSpace.SeparableSpace (Ambient a) ∧
59 UniformConvexSpace (Ambient a) ∧
60 HasRealBanachLatticeOrder (Ambient a) ∧
61 ∃ P : Ambient a →L[ℝ] Ambient a,
62 P.comp P = P ∧
63 ‖P‖ < 1 + ρ ∧
64 ‖ContinuousLinearMap.id ℝ (Ambient a) - P‖ < 1 + ρ ∧
65 HasSeparatedRange P ∧
66 HasSeparatedRange (ContinuousLinearMap.id ℝ (Ambient a) - P)
67
68end ComplementedSubspace