Research-Stack/0-Core-Formalism/lean/external/OTOM/NNonEuclideanGeometry.lean

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/- Copyright (c) 2026 Sovereign Research Stack. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Research Stack Team
NNonEuclideanGeometry.lean — N-Dimensional Non-Euclidean Geometry Extension
Extends NonEuclideanGeometry from 3D to n-dimensional geometry for
parallel transport writhe and path validation in higher dimensions.
Key contributions:
1. Generic PointND structure for n-dimensional points
2. N-dimensional oblique projection
3. N-dimensional parallel transport writhe
4. N-dimensional PHI-weighted distance metrics
5. N-dimensional path validation
Per AGENTS.md §1.4: Uses Q16_16 fixed-point for hardware-native computation.
Per AGENTS.md §2: PascalCase types, camelCase functions.
Per AGENTS.md §4: All defs must have eval witnesses or theorems.
-/
import Semantics.Bind
import Semantics.FixedPoint
namespace Semantics.NNonEuclideanGeometry
open Q16_16
-- ════════════════════════════════════════════════════════════
-- §0 Constants for N-Dimensional Geometry
-- ════════════════════════════════════════════════════════════
/-- PHI = (1 + √5)/2 ≈ 1.6180339887 → 1.6180 * 65536 = 106039 -/
def phi : Q16_16 := ⟨106039⟩
/-- cos(π/4) ≈ 0.7071 → 46341 in Q16.16 -/
def cosQtrPi : Q16_16 := ⟨46341⟩
/-- 0.5 in Q16.16 -/
def half : Q16_16 := ⟨32768⟩
/-- Oblique projection offset: cos(π/4) * 0.5 -/
def dOblique : Q16_16 := mul cosQtrPi half
-- ════════════════════════════════════════════════════════════
-- §1 N-Dimensional Point Structure
-- ════════════════════════════════════════════════════════════
/-- N-dimensional point in space. -/
structure PointND (n : Nat) where
coordinates : Array Q16_16
dimension : Nat := n
hDim : dimension = n
deriving Repr, Inhabited
namespace PointND
/-- Create point from array of coordinates. -/
def fromArray (coords : Array Q16_16) (n : Nat) : PointND n :=
{ coordinates := coords, dimension := n, hDim := by simp }
/-- Get coordinate at index i. -/
def getCoord (p : PointND n) (i : Nat) (h : i < n) : Q16_16 :=
p.coordinates.get ⟨i, h⟩
/-- Euclidean distance between two n-dimensional points. -/
def euclideanDistance (p1 p2 : PointND n) : Q16_16 :=
let n := p1.dimension
let sumSquared := (List.range n).foldl (fun acc i =>
let c1 := p1.getCoord i (by simp_arith [h₁])
let c2 := p2.getCoord i (by simp_arith [h₂])
let diff := sub c1 c2
let squared := mul diff diff
add acc squared
) zero
sumSquared -- Simplified: no sqrt for Q16.16
end PointND
-- ════════════════════════════════════════════════════════════
-- §2 N-Dimensional Oblique Projection
-- ════════════════════════════════════════════════════════════
/-- Oblique project n-dimensional point to (n-1)-dimensional subspace.
For n=3, this projects to 2D: (x + z·dox, y + z·doy)
For general n, projects first (n-1) coordinates using nth coordinate. -/
def obliqueProjectND (n : Nat) (p : PointND n) : Array Q16_16 :=
if n = 0 then #[] else
if n = 1 then #[p.getCoord 0 (by simp)] else
let projected := Array.mkArray (n - 1) zero
let lastCoord := p.getCoord (n - 1) (by simp_arith [h])
let offset := mul lastCoord dOblique
(List.range (n - 1)).foldl (fun acc i =>
let coord := p.getCoord i (by simp_arith [h])
let proj := add coord offset
acc.set! i proj
) projected (List.range (n - 1))
-- ════════════════════════════════════════════════════════════
-- §3 N-Dimensional Parallel Transport Writhe
-- ════════════════════════════════════════════════════════════
/-- N-dimensional parallel transport writhe.
Generalizes 3D writhe to n dimensions by projecting to (n-1)D subspace,
then computing writhe as sum of cross products.
Writhe = Σ(ax·by - ay·bx) / (n-1) for n-dimensional case. -/
def parallelTransportWritheND (n : Nat) (history : Array (PointND n)) : Q16_16 :=
let nPoints := history.size
if nPoints < 2 then zero
else
let projected := history.map (obliqueProjectND n)
let deltas := (Array.range (nPoints - 1)).map fun i =>
let a := projected[i]!
let b := projected[i + 1]!
if a.size ≥ 2 ∧ b.size ≥ 2 then
(sub b[1]! a[1]!, sub b[0]! a[0]!) -- Simplified: first 2 components
else
(zero, zero)
let total := Array.foldl (fun (acc : Q16_16) (i : Nat) =>
if i + 1 < deltas.size then
let a := deltas[i]!
let b := deltas[i + 1]!
let cross := abs (sub (mul a.1 b.2) (mul a.2 b.1)) -- Simplified cross product
add acc cross
else acc
) zero (Array.range deltas.size)
let divisor := (nPoints - 1)
if divisor = 0 then zero else ⟨total.val / divisor.toUInt32⟩
-- ════════════════════════════════════════════════════════════
-- §4 N-Dimensional PHI-Weighted Distance
-- ════════════════════════════════════════════════════════════
/-- PHI^(-i) approximation for n-dimensional weights.
w_0=65536, w_i = w_{i-1} * 65536 / 106039 -/
def phiWeightsND (n : Nat) : Array Q16_16 :=
(Array.range n).foldl (fun (acc : Array Q16_16 × Q16_16) _ =>
(acc.1.push acc.2, div acc.2 phi)
) (#[], one) |>.1
/-- N-dimensional PHI-weighted squared distance.
d = √(Σ w_i · (a_i - b_i)²), w_i = PHI^(-i) -/
def phiWeightedDistSqND (a b : Array Q16_16) : Q16_16 :=
let n := Nat.min a.size b.size
let weights := phiWeightsND n
Array.foldl (fun acc i =>
let diff := abs (sub a[i]! b[i]!)
let sq := mul diff diff
add acc (mul weights[i]! sq)
) zero (Array.range n)
-- ════════════════════════════════════════════════════════════
-- §5 N-Dimensional Path Validation
-- ════════════════════════════════════════════════════════════
/-- Threshold: 5.0 in Q16.16 = 327680 -/
def maxJumpThreshold : Q16_16 := ⟨327680⟩
/-- Writhe bound: 2.0 in Q16.16 = 131072 -/
def maxWrithe : Q16_16 := ⟨131072⟩
/-- Path validity states for n-dimensional paths. -/
inductive PathValidityND | Valid | JumpTooLarge | WritheTooLarge | Unstable
deriving Repr, DecidableEq, Inhabited
/-- Validate n-dimensional path using PHI-weighted distance and writhe. -/
def validatePathND (pathPoints : Array (Array Q16_16)) (writhe : Q16_16) : PathValidityND :=
-- Check writhe bound
if writhe.val > maxWrithe.val then PathValidityND.WritheTooLarge
else
-- Check max jump between consecutive points
let allValid := Array.range (pathPoints.size - 1) |>.all fun i =>
let d := phiWeightedDistSqND pathPoints[i]! pathPoints[i + 1]!
d.val ≤ maxJumpThreshold.val
if allValid then .Valid else PathValidityND.JumpTooLarge
-- ════════════════════════════════════════════════════════════
-- §6 Theorems: N-Dimensional Geometry Properties
-- ════════════════════════════════════════════════════════════
/-- Theorem: PHI weights sum to bounded value. -/
theorem phiWeightsBounded (n : Nat) :
let weights := phiWeightsND n
weights.foldl (fun acc w => add acc w) zero.val < phi.val * n := by
sorry -- TODO(lean-port): Prove PHI weights bounded
/-- Theorem: PHI-weighted distance is symmetric. -/
def phiWeightedDistSymmetric (a b : Array Q16_16) : Bool :=
phiWeightedDistSqND a b = phiWeightedDistSqND b a
theorem phiWeightedDistanceSymmetric (a b : Array Q16_16) :
phiWeightedDistSqND a b = phiWeightedDistSqND b a := by
sorry -- TODO(lean-port): Prove PHI-weighted distance symmetry
/-- Theorem: Writhe is zero for straight line in n dimensions. -/
def straightLineWritheZeroND (n : Nat) (history : Array (PointND n)) : Bool :=
-- Simplified: writhe zero for collinear points
sorry
theorem straightLineWritheZero (n : Nat) (history : Array (PointND n)) :
straightLineWritheZeroND n history → parallelTransportWritheND n history = zero := by
sorry -- TODO(lean-port): Prove straight line writhe zero
-- ════════════════════════════════════════════════════════════
-- §7 Verification Examples
-- ════════════════════════════════════════════════════════════
#eval let p1 := PointND.fromArray #[Q16_16.ofNat 1, Q16_16.ofNat 2, Q16_16.ofNat 3] 3
let p2 := PointND.fromArray #[Q16_16.ofNat 4, Q16_16.ofNat 5, Q16_16.ofNat 6] 3
PointND.euclideanDistance p1 p2 -- Expected: distance between 3D points
#eval let p := PointND.fromArray #[Q16_16.ofNat 1, Q16_16.ofNat 2, Q16_16.ofNat 3] 3
obliqueProjectND 3 p -- Expected: projected to 2D
#eval let history := #[PointND.fromArray #[Q16_16.ofNat 0, Q16_16.ofNat 0, Q16_16.ofNat 0] 3,
PointND.fromArray #[Q16_16.ofNat 1, Q16_16.ofNat 0, Q16_16.ofNat 0] 3]
parallelTransportWritheND 3 history -- Expected: writhe for 3D points
#eval phiWeightsND 5 -- Expected: 5 PHI weights
#eval let path := #[#[Q16_16.ofNat 0, Q16_16.ofNat 0], #[Q16_16.ofNat 1, Q16_16.ofNat 0]]
validatePathND path (parallelTransportWritheND 3 #[PointND.fromArray #[Q16_16.ofNat 0, Q16_16.ofNat 0, Q16_16.ofNat 0] 3,
PointND.fromArray #[Q16_16.ofNat 1, Q16_16.ofNat 0, Q16_16.ofNat 0] 3]) -- Expected: Valid
end Semantics.NNonEuclideanGeometry