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NonContradictionOn
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IndisputableMonolith.Foundation.DomainBootstrap on GitHub at line 69.
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66 ∀ x : K, 0 < x → C x x = 0
67
68/-- Non-contradiction, generic field version. -/
69def NonContradictionOn [LT K] [Zero K] (C : ComparisonOperatorOn K) : Prop :=
70 ∀ x y : K, 0 < x → 0 < y → C x y = C y x
71
72/-- Scale invariance, generic field version. -/
73def ScaleInvariantOn [Zero K] [LT K] [Mul K] (C : ComparisonOperatorOn K) : Prop :=
74 ∀ x y lam : K, 0 < x → 0 < y → 0 < lam →
75 C (lam * x) (lam * y) = C x y
76
77/-- Distinguishability, generic field version. -/
78def DistinguishabilityOn [Zero K] [LT K] (C : ComparisonOperatorOn K) : Prop :=
79 ∃ x y : K, 0 < x ∧ 0 < y ∧ C x y ≠ 0
80
81/-! ## 2. The bootstrap theorem
82
83The Law of Logic on an ambient field `K` plus Archimedean +
84Dedekind-completeness implies `K ≃+*o ℝ`. The proof is by reduction
85to Mathlib's classical characterization of `ℝ`.
86
87The completeness hypothesis is the standard analytic input that makes
88"continuous comparison" non-vacuous; without it, the comparison
89operator could live on `ℚ` or any incomplete subfield. With it, `K`
90is forced to be `ℝ`.
91-/
92
93/-- A linearly ordered field is **Logic-supported** when a comparison
94operator on it satisfies the four Aristotelian conditions plus scale
95invariance and distinguishability. We package the ordered-field
96structure required to even *state* these conditions. -/
97structure LogicSupported (K : Type*) [Mul K] [Zero K] [One K] [LT K] where
98 zero_lt_one_in_K : (0 : K) < 1
99 C : ComparisonOperatorOn K