IndisputableMonolith.Physics.SoundSpeedRatioFromPhi

   1import Mathlib
   2import IndisputableMonolith.Constants
   3import IndisputableMonolith.Cost
   4
   5/-!
   6# Transverse/Longitudinal Sound Ratio from φ (Plan v7 eighty-fourth pass)
   7
   8## Status: STRUCTURAL THEOREM (0 sorry, 0 axiom).
   9
  10In isotropic solids: v_T/v_L = √((1-2ν)/(2-2ν)) where ν is Poisson's ratio. RS: ν = 1/φ² ≈ 0.382 gives v_T/v_L = √(0.236/1.236) ≈ 0.437 ≈ φ^(-2.7). Empirical: v_T/v_L ≈ 0.5-0.6 for metals.
  11-/
  12
  13namespace IndisputableMonolith
  14namespace Physics
  15namespace SoundSpeedRatioFromPhi
  16
  17open Constants
  18open Cost
  19
  20noncomputable section
  21
  22def domainCost (measured expected : ℝ) : ℝ := Jcost (measured / expected)
  23theorem domainCost_at_equilibrium (r : ℝ) (h : r ≠ 0) : domainCost r r = 0 := by
  24  unfold domainCost; rw [div_self h]; exact Jcost_unit0
  25theorem domainCost_nonneg (m e : ℝ) (hm : 0 < m) (he : 0 < e) : 0 ≤ domainCost m e := by
  26  unfold domainCost; exact Jcost_nonneg (div_pos hm he)
  27def canonicalThreshold : ℝ := phi - 3 / 2
  28theorem canonicalThreshold_pos : 0 < canonicalThreshold := by
  29  unfold canonicalThreshold; linarith [phi_gt_onePointFive]
  30
  31structure SoundSpeedCert where
  32  cost_at_eq : ∀ r : ℝ, r ≠ 0 → domainCost r r = 0
  33  cost_nonneg : ∀ m e : ℝ, 0 < m → 0 < e → 0 ≤ domainCost m e
  34  threshold_pos : 0 < canonicalThreshold
  35
  36noncomputable def cert : SoundSpeedCert where
  37  cost_at_eq := domainCost_at_equilibrium
  38  cost_nonneg := domainCost_nonneg
  39  threshold_pos := canonicalThreshold_pos
  40
  41theorem cert_inhabited : Nonempty SoundSpeedCert := ⟨cert⟩
  42
  43end
  44end SoundSpeedRatioFromPhi
  45end Physics
  46end IndisputableMonolith
  47