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Description: Ordering on reals satisfies strict trichotomy. Axiom 18 of 22 for real and complex numbers, justified by Theorem axpre-lttri . Note: The more general version for extended reals is axlttri . Normally new proofs would use xrlttri . (New usage is discouraged.) (Contributed by NM, 13-Oct-2005)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ax-pre-lttri | ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) → ( 𝐴 <ℝ 𝐵 ↔ ¬ ( 𝐴 = 𝐵 ∨ 𝐵 <ℝ 𝐴 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cA | ⊢ 𝐴 | |
| 1 | cr | ⊢ ℝ | |
| 2 | 0 1 | wcel | ⊢ 𝐴 ∈ ℝ |
| 3 | cB | ⊢ 𝐵 | |
| 4 | 3 1 | wcel | ⊢ 𝐵 ∈ ℝ |
| 5 | 2 4 | wa | ⊢ ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) |
| 6 | cltrr | ⊢ <ℝ | |
| 7 | 0 3 6 | wbr | ⊢ 𝐴 <ℝ 𝐵 |
| 8 | 0 3 | wceq | ⊢ 𝐴 = 𝐵 |
| 9 | 3 0 6 | wbr | ⊢ 𝐵 <ℝ 𝐴 |
| 10 | 8 9 | wo | ⊢ ( 𝐴 = 𝐵 ∨ 𝐵 <ℝ 𝐴 ) |
| 11 | 10 | wn | ⊢ ¬ ( 𝐴 = 𝐵 ∨ 𝐵 <ℝ 𝐴 ) |
| 12 | 7 11 | wb | ⊢ ( 𝐴 <ℝ 𝐵 ↔ ¬ ( 𝐴 = 𝐵 ∨ 𝐵 <ℝ 𝐴 ) ) |
| 13 | 5 12 | wi | ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) → ( 𝐴 <ℝ 𝐵 ↔ ¬ ( 𝐴 = 𝐵 ∨ 𝐵 <ℝ 𝐴 ) ) ) |