lemma
proved
zero_normalization_forces_offset
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IndisputableMonolith.Masses.GapFunctionForcing on GitHub at line 66.
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63 simp [hshift]
64
65/-- Neutral normalization fixes the additive offset. -/
66lemma zero_normalization_forces_offset
67 {a c : ℝ}
68 (h0 : gapAffineLogR a phi c 0 = 0) :
69 c = 0 := by
70 simpa [gapAffineLogR] using h0
71
72/-- Unit-step calibration fixes the log scale coefficient. -/
73lemma unit_step_forces_log_scale
74 {a c : ℝ}
75 (h0 : gapAffineLogR a phi c 0 = 0)
76 (h1 : gapAffineLogR a phi c 1 = 1) :
77 a = 1 / Real.log phi := by
78 have hc : c = 0 := zero_normalization_forces_offset h0
79 have hlog_ne : Real.log phi ≠ 0 := ne_of_gt (Real.log_pos one_lt_phi)
80 have hmul_raw : a * Real.log (1 + phi⁻¹) = 1 := by
81 simpa [gapAffineLogR, hc] using h1
82 have hmul : a * Real.log phi = 1 := by
83 calc
84 a * Real.log phi = a * Real.log (1 + phi⁻¹) := by
85 rw [log_one_add_inv_phi_eq_log_phi]
86 _ = 1 := hmul_raw
87 exact (eq_div_iff hlog_ne).2 hmul
88
89/-- Three-point calibration (`x = -1,0,1`) forces the affine-log shift to `b = φ`.
90 The extra `b > 1` assumption encodes the physically relevant positive-shift branch. -/
91lemma minus_one_step_forces_phi_shift
92 {a b c : ℝ}
93 (hb : 1 < b)
94 (h0 : gapAffineLogR a b c 0 = 0)
95 (h1 : gapAffineLogR a b c 1 = 1)
96 (hneg1 : gapAffineLogR a b c (-1) = -2) :