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Description: Equality in terms of 'less than or equal to', 'less than'. (Contributed by NM, 7-Apr-2001)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | ltd.1 | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| ltd.2 | ⊢ ( 𝜑 → 𝐵 ∈ ℝ ) | ||
| Assertion | eqleltd | ⊢ ( 𝜑 → ( 𝐴 = 𝐵 ↔ ( 𝐴 ≤ 𝐵 ∧ ¬ 𝐴 < 𝐵 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ltd.1 | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| 2 | ltd.2 | ⊢ ( 𝜑 → 𝐵 ∈ ℝ ) | |
| 3 | eqlelt | ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) → ( 𝐴 = 𝐵 ↔ ( 𝐴 ≤ 𝐵 ∧ ¬ 𝐴 < 𝐵 ) ) ) | |
| 4 | 1 2 3 | syl2anc | ⊢ ( 𝜑 → ( 𝐴 = 𝐵 ↔ ( 𝐴 ≤ 𝐵 ∧ ¬ 𝐴 < 𝐵 ) ) ) |