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Description: The completeness axiom for reals in terms of infimum: a nonempty, bounded-below set of reals has an infimum. (This theorem is the dual of sup3 .) (Contributed by NM, 14-Jun-2005)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | infm3 | ⊢ ( ( 𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅ ∧ ∃ 𝑥 ∈ ℝ ∀ 𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ) → ∃ 𝑥 ∈ ℝ ( ∀ 𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥 ∧ ∀ 𝑦 ∈ ℝ ( 𝑥 < 𝑦 → ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ssel | ⊢ ( 𝐴 ⊆ ℝ → ( 𝑣 ∈ 𝐴 → 𝑣 ∈ ℝ ) ) | |
| 2 | 1 | pm4.71rd | ⊢ ( 𝐴 ⊆ ℝ → ( 𝑣 ∈ 𝐴 ↔ ( 𝑣 ∈ ℝ ∧ 𝑣 ∈ 𝐴 ) ) ) |
| 3 | 2 | exbidv | ⊢ ( 𝐴 ⊆ ℝ → ( ∃ 𝑣 𝑣 ∈ 𝐴 ↔ ∃ 𝑣 ( 𝑣 ∈ ℝ ∧ 𝑣 ∈ 𝐴 ) ) ) |
| 4 | df-rex | ⊢ ( ∃ 𝑣 ∈ ℝ 𝑣 ∈ 𝐴 ↔ ∃ 𝑣 ( 𝑣 ∈ ℝ ∧ 𝑣 ∈ 𝐴 ) ) | |
| 5 | renegcl | ⊢ ( 𝑤 ∈ ℝ → - 𝑤 ∈ ℝ ) | |
| 6 | infm3lem | ⊢ ( 𝑣 ∈ ℝ → ∃ 𝑤 ∈ ℝ 𝑣 = - 𝑤 ) | |
| 7 | eleq1 | ⊢ ( 𝑣 = - 𝑤 → ( 𝑣 ∈ 𝐴 ↔ - 𝑤 ∈ 𝐴 ) ) | |
| 8 | 5 6 7 | rexxfr | ⊢ ( ∃ 𝑣 ∈ ℝ 𝑣 ∈ 𝐴 ↔ ∃ 𝑤 ∈ ℝ - 𝑤 ∈ 𝐴 ) |
| 9 | 4 8 | bitr3i | ⊢ ( ∃ 𝑣 ( 𝑣 ∈ ℝ ∧ 𝑣 ∈ 𝐴 ) ↔ ∃ 𝑤 ∈ ℝ - 𝑤 ∈ 𝐴 ) |
| 10 | 3 9 | bitrdi | ⊢ ( 𝐴 ⊆ ℝ → ( ∃ 𝑣 𝑣 ∈ 𝐴 ↔ ∃ 𝑤 ∈ ℝ - 𝑤 ∈ 𝐴 ) ) |
| 11 | n0 | ⊢ ( 𝐴 ≠ ∅ ↔ ∃ 𝑣 𝑣 ∈ 𝐴 ) | |
| 12 | rabn0 | ⊢ ( { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ≠ ∅ ↔ ∃ 𝑤 ∈ ℝ - 𝑤 ∈ 𝐴 ) | |
| 13 | 10 11 12 | 3bitr4g | ⊢ ( 𝐴 ⊆ ℝ → ( 𝐴 ≠ ∅ ↔ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ≠ ∅ ) ) |
| 14 | ssel | ⊢ ( 𝐴 ⊆ ℝ → ( 𝑦 ∈ 𝐴 → 𝑦 ∈ ℝ ) ) | |
| 15 | 14 | pm4.71rd | ⊢ ( 𝐴 ⊆ ℝ → ( 𝑦 ∈ 𝐴 ↔ ( 𝑦 ∈ ℝ ∧ 𝑦 ∈ 𝐴 ) ) ) |
| 16 | 15 | imbi1d | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ↔ ( ( 𝑦 ∈ ℝ ∧ 𝑦 ∈ 𝐴 ) → 𝑥 ≤ 𝑦 ) ) ) |
| 17 | impexp | ⊢ ( ( ( 𝑦 ∈ ℝ ∧ 𝑦 ∈ 𝐴 ) → 𝑥 ≤ 𝑦 ) ↔ ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ) ) | |
| 18 | 16 17 | bitrdi | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ↔ ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ) ) ) |
| 19 | 18 | albidv | ⊢ ( 𝐴 ⊆ ℝ → ( ∀ 𝑦 ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ↔ ∀ 𝑦 ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ) ) ) |
| 20 | df-ral | ⊢ ( ∀ 𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ↔ ∀ 𝑦 ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ) | |
| 21 | renegcl | ⊢ ( 𝑣 ∈ ℝ → - 𝑣 ∈ ℝ ) | |
| 22 | infm3lem | ⊢ ( 𝑦 ∈ ℝ → ∃ 𝑣 ∈ ℝ 𝑦 = - 𝑣 ) | |
| 23 | eleq1 | ⊢ ( 𝑦 = - 𝑣 → ( 𝑦 ∈ 𝐴 ↔ - 𝑣 ∈ 𝐴 ) ) | |
| 24 | breq2 | ⊢ ( 𝑦 = - 𝑣 → ( 𝑥 ≤ 𝑦 ↔ 𝑥 ≤ - 𝑣 ) ) | |
| 25 | 23 24 | imbi12d | ⊢ ( 𝑦 = - 𝑣 → ( ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ↔ ( - 𝑣 ∈ 𝐴 → 𝑥 ≤ - 𝑣 ) ) ) |
| 26 | 21 22 25 | ralxfr | ⊢ ( ∀ 𝑦 ∈ ℝ ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑥 ≤ - 𝑣 ) ) |
| 27 | df-ral | ⊢ ( ∀ 𝑦 ∈ ℝ ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ↔ ∀ 𝑦 ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ) ) | |
| 28 | 26 27 | bitr3i | ⊢ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑥 ≤ - 𝑣 ) ↔ ∀ 𝑦 ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → 𝑥 ≤ 𝑦 ) ) ) |
| 29 | 19 20 28 | 3bitr4g | ⊢ ( 𝐴 ⊆ ℝ → ( ∀ 𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑥 ≤ - 𝑣 ) ) ) |
| 30 | 29 | rexbidv | ⊢ ( 𝐴 ⊆ ℝ → ( ∃ 𝑥 ∈ ℝ ∀ 𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ↔ ∃ 𝑥 ∈ ℝ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑥 ≤ - 𝑣 ) ) ) |
| 31 | renegcl | ⊢ ( 𝑢 ∈ ℝ → - 𝑢 ∈ ℝ ) | |
| 32 | infm3lem | ⊢ ( 𝑥 ∈ ℝ → ∃ 𝑢 ∈ ℝ 𝑥 = - 𝑢 ) | |
| 33 | breq1 | ⊢ ( 𝑥 = - 𝑢 → ( 𝑥 ≤ - 𝑣 ↔ - 𝑢 ≤ - 𝑣 ) ) | |
| 34 | 33 | imbi2d | ⊢ ( 𝑥 = - 𝑢 → ( ( - 𝑣 ∈ 𝐴 → 𝑥 ≤ - 𝑣 ) ↔ ( - 𝑣 ∈ 𝐴 → - 𝑢 ≤ - 𝑣 ) ) ) |
| 35 | 34 | ralbidv | ⊢ ( 𝑥 = - 𝑢 → ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑥 ≤ - 𝑣 ) ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → - 𝑢 ≤ - 𝑣 ) ) ) |
| 36 | 31 32 35 | rexxfr | ⊢ ( ∃ 𝑥 ∈ ℝ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑥 ≤ - 𝑣 ) ↔ ∃ 𝑢 ∈ ℝ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → - 𝑢 ≤ - 𝑣 ) ) |
| 37 | negeq | ⊢ ( 𝑤 = 𝑣 → - 𝑤 = - 𝑣 ) | |
| 38 | 37 | eleq1d | ⊢ ( 𝑤 = 𝑣 → ( - 𝑤 ∈ 𝐴 ↔ - 𝑣 ∈ 𝐴 ) ) |
| 39 | 38 | elrab | ⊢ ( 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ↔ ( 𝑣 ∈ ℝ ∧ - 𝑣 ∈ 𝐴 ) ) |
| 40 | 39 | imbi1i | ⊢ ( ( 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } → 𝑣 ≤ 𝑢 ) ↔ ( ( 𝑣 ∈ ℝ ∧ - 𝑣 ∈ 𝐴 ) → 𝑣 ≤ 𝑢 ) ) |
| 41 | impexp | ⊢ ( ( ( 𝑣 ∈ ℝ ∧ - 𝑣 ∈ 𝐴 ) → 𝑣 ≤ 𝑢 ) ↔ ( 𝑣 ∈ ℝ → ( - 𝑣 ∈ 𝐴 → 𝑣 ≤ 𝑢 ) ) ) | |
| 42 | 40 41 | bitri | ⊢ ( ( 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } → 𝑣 ≤ 𝑢 ) ↔ ( 𝑣 ∈ ℝ → ( - 𝑣 ∈ 𝐴 → 𝑣 ≤ 𝑢 ) ) ) |
| 43 | 42 | albii | ⊢ ( ∀ 𝑣 ( 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } → 𝑣 ≤ 𝑢 ) ↔ ∀ 𝑣 ( 𝑣 ∈ ℝ → ( - 𝑣 ∈ 𝐴 → 𝑣 ≤ 𝑢 ) ) ) |
| 44 | df-ral | ⊢ ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 ≤ 𝑢 ↔ ∀ 𝑣 ( 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } → 𝑣 ≤ 𝑢 ) ) | |
| 45 | df-ral | ⊢ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑣 ≤ 𝑢 ) ↔ ∀ 𝑣 ( 𝑣 ∈ ℝ → ( - 𝑣 ∈ 𝐴 → 𝑣 ≤ 𝑢 ) ) ) | |
| 46 | 43 44 45 | 3bitr4ri | ⊢ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑣 ≤ 𝑢 ) ↔ ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 ≤ 𝑢 ) |
| 47 | leneg | ⊢ ( ( 𝑣 ∈ ℝ ∧ 𝑢 ∈ ℝ ) → ( 𝑣 ≤ 𝑢 ↔ - 𝑢 ≤ - 𝑣 ) ) | |
| 48 | 47 | ancoms | ⊢ ( ( 𝑢 ∈ ℝ ∧ 𝑣 ∈ ℝ ) → ( 𝑣 ≤ 𝑢 ↔ - 𝑢 ≤ - 𝑣 ) ) |
| 49 | 48 | imbi2d | ⊢ ( ( 𝑢 ∈ ℝ ∧ 𝑣 ∈ ℝ ) → ( ( - 𝑣 ∈ 𝐴 → 𝑣 ≤ 𝑢 ) ↔ ( - 𝑣 ∈ 𝐴 → - 𝑢 ≤ - 𝑣 ) ) ) |
| 50 | 49 | ralbidva | ⊢ ( 𝑢 ∈ ℝ → ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑣 ≤ 𝑢 ) ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → - 𝑢 ≤ - 𝑣 ) ) ) |
| 51 | 46 50 | bitr3id | ⊢ ( 𝑢 ∈ ℝ → ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 ≤ 𝑢 ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → - 𝑢 ≤ - 𝑣 ) ) ) |
| 52 | 51 | rexbiia | ⊢ ( ∃ 𝑢 ∈ ℝ ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 ≤ 𝑢 ↔ ∃ 𝑢 ∈ ℝ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → - 𝑢 ≤ - 𝑣 ) ) |
| 53 | 36 52 | bitr4i | ⊢ ( ∃ 𝑥 ∈ ℝ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → 𝑥 ≤ - 𝑣 ) ↔ ∃ 𝑢 ∈ ℝ ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 ≤ 𝑢 ) |
| 54 | 30 53 | bitrdi | ⊢ ( 𝐴 ⊆ ℝ → ( ∃ 𝑥 ∈ ℝ ∀ 𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ↔ ∃ 𝑢 ∈ ℝ ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 ≤ 𝑢 ) ) |
| 55 | 13 54 | anbi12d | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝐴 ≠ ∅ ∧ ∃ 𝑥 ∈ ℝ ∀ 𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ) ↔ ( { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ≠ ∅ ∧ ∃ 𝑢 ∈ ℝ ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 ≤ 𝑢 ) ) ) |
| 56 | ssrab2 | ⊢ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ⊆ ℝ | |
| 57 | sup3 | ⊢ ( ( { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ⊆ ℝ ∧ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ≠ ∅ ∧ ∃ 𝑢 ∈ ℝ ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 ≤ 𝑢 ) → ∃ 𝑢 ∈ ℝ ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ∧ ∀ 𝑣 ∈ ℝ ( 𝑣 < 𝑢 → ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ) ) ) | |
| 58 | 56 57 | mp3an1 | ⊢ ( ( { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ≠ ∅ ∧ ∃ 𝑢 ∈ ℝ ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 ≤ 𝑢 ) → ∃ 𝑢 ∈ ℝ ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ∧ ∀ 𝑣 ∈ ℝ ( 𝑣 < 𝑢 → ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ) ) ) |
| 59 | 55 58 | biimtrdi | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝐴 ≠ ∅ ∧ ∃ 𝑥 ∈ ℝ ∀ 𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ) → ∃ 𝑢 ∈ ℝ ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ∧ ∀ 𝑣 ∈ ℝ ( 𝑣 < 𝑢 → ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ) ) ) ) |
| 60 | 15 | imbi1d | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ↔ ( ( 𝑦 ∈ ℝ ∧ 𝑦 ∈ 𝐴 ) → ¬ 𝑦 < 𝑥 ) ) ) |
| 61 | impexp | ⊢ ( ( ( 𝑦 ∈ ℝ ∧ 𝑦 ∈ 𝐴 ) → ¬ 𝑦 < 𝑥 ) ↔ ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ) ) | |
| 62 | 60 61 | bitrdi | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ↔ ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ) ) ) |
| 63 | 62 | albidv | ⊢ ( 𝐴 ⊆ ℝ → ( ∀ 𝑦 ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ↔ ∀ 𝑦 ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ) ) ) |
| 64 | df-ral | ⊢ ( ∀ 𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥 ↔ ∀ 𝑦 ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ) | |
| 65 | breq1 | ⊢ ( 𝑦 = - 𝑣 → ( 𝑦 < 𝑥 ↔ - 𝑣 < 𝑥 ) ) | |
| 66 | 65 | notbid | ⊢ ( 𝑦 = - 𝑣 → ( ¬ 𝑦 < 𝑥 ↔ ¬ - 𝑣 < 𝑥 ) ) |
| 67 | 23 66 | imbi12d | ⊢ ( 𝑦 = - 𝑣 → ( ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ↔ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ) ) |
| 68 | 21 22 67 | ralxfr | ⊢ ( ∀ 𝑦 ∈ ℝ ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ) |
| 69 | df-ral | ⊢ ( ∀ 𝑦 ∈ ℝ ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ↔ ∀ 𝑦 ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ) ) | |
| 70 | 68 69 | bitr3i | ⊢ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ↔ ∀ 𝑦 ( 𝑦 ∈ ℝ → ( 𝑦 ∈ 𝐴 → ¬ 𝑦 < 𝑥 ) ) ) |
| 71 | 63 64 70 | 3bitr4g | ⊢ ( 𝐴 ⊆ ℝ → ( ∀ 𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥 ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ) ) |
| 72 | breq2 | ⊢ ( 𝑦 = - 𝑣 → ( 𝑥 < 𝑦 ↔ 𝑥 < - 𝑣 ) ) | |
| 73 | breq2 | ⊢ ( 𝑦 = - 𝑣 → ( 𝑧 < 𝑦 ↔ 𝑧 < - 𝑣 ) ) | |
| 74 | 73 | rexbidv | ⊢ ( 𝑦 = - 𝑣 → ( ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ↔ ∃ 𝑧 ∈ 𝐴 𝑧 < - 𝑣 ) ) |
| 75 | 72 74 | imbi12d | ⊢ ( 𝑦 = - 𝑣 → ( ( 𝑥 < 𝑦 → ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ) ↔ ( 𝑥 < - 𝑣 → ∃ 𝑧 ∈ 𝐴 𝑧 < - 𝑣 ) ) ) |
| 76 | 21 22 75 | ralxfr | ⊢ ( ∀ 𝑦 ∈ ℝ ( 𝑥 < 𝑦 → ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ) ↔ ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑧 ∈ 𝐴 𝑧 < - 𝑣 ) ) |
| 77 | ssel | ⊢ ( 𝐴 ⊆ ℝ → ( 𝑧 ∈ 𝐴 → 𝑧 ∈ ℝ ) ) | |
| 78 | 77 | adantrd | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) → 𝑧 ∈ ℝ ) ) |
| 79 | 78 | pm4.71rd | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ↔ ( 𝑧 ∈ ℝ ∧ ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ) ) ) |
| 80 | 79 | exbidv | ⊢ ( 𝐴 ⊆ ℝ → ( ∃ 𝑧 ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ↔ ∃ 𝑧 ( 𝑧 ∈ ℝ ∧ ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ) ) ) |
| 81 | df-rex | ⊢ ( ∃ 𝑧 ∈ 𝐴 𝑧 < - 𝑣 ↔ ∃ 𝑧 ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ) | |
| 82 | renegcl | ⊢ ( 𝑡 ∈ ℝ → - 𝑡 ∈ ℝ ) | |
| 83 | infm3lem | ⊢ ( 𝑧 ∈ ℝ → ∃ 𝑡 ∈ ℝ 𝑧 = - 𝑡 ) | |
| 84 | eleq1 | ⊢ ( 𝑧 = - 𝑡 → ( 𝑧 ∈ 𝐴 ↔ - 𝑡 ∈ 𝐴 ) ) | |
| 85 | breq1 | ⊢ ( 𝑧 = - 𝑡 → ( 𝑧 < - 𝑣 ↔ - 𝑡 < - 𝑣 ) ) | |
| 86 | 84 85 | anbi12d | ⊢ ( 𝑧 = - 𝑡 → ( ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ↔ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) |
| 87 | 82 83 86 | rexxfr | ⊢ ( ∃ 𝑧 ∈ ℝ ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ↔ ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) |
| 88 | df-rex | ⊢ ( ∃ 𝑧 ∈ ℝ ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ↔ ∃ 𝑧 ( 𝑧 ∈ ℝ ∧ ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ) ) | |
| 89 | 87 88 | bitr3i | ⊢ ( ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ↔ ∃ 𝑧 ( 𝑧 ∈ ℝ ∧ ( 𝑧 ∈ 𝐴 ∧ 𝑧 < - 𝑣 ) ) ) |
| 90 | 80 81 89 | 3bitr4g | ⊢ ( 𝐴 ⊆ ℝ → ( ∃ 𝑧 ∈ 𝐴 𝑧 < - 𝑣 ↔ ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) |
| 91 | 90 | imbi2d | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝑥 < - 𝑣 → ∃ 𝑧 ∈ 𝐴 𝑧 < - 𝑣 ) ↔ ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) |
| 92 | 91 | ralbidv | ⊢ ( 𝐴 ⊆ ℝ → ( ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑧 ∈ 𝐴 𝑧 < - 𝑣 ) ↔ ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) |
| 93 | 76 92 | bitrid | ⊢ ( 𝐴 ⊆ ℝ → ( ∀ 𝑦 ∈ ℝ ( 𝑥 < 𝑦 → ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ) ↔ ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) |
| 94 | 71 93 | anbi12d | ⊢ ( 𝐴 ⊆ ℝ → ( ( ∀ 𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥 ∧ ∀ 𝑦 ∈ ℝ ( 𝑥 < 𝑦 → ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ) ) ↔ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ∧ ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) ) |
| 95 | 94 | rexbidv | ⊢ ( 𝐴 ⊆ ℝ → ( ∃ 𝑥 ∈ ℝ ( ∀ 𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥 ∧ ∀ 𝑦 ∈ ℝ ( 𝑥 < 𝑦 → ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ) ) ↔ ∃ 𝑥 ∈ ℝ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ∧ ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) ) |
| 96 | breq2 | ⊢ ( 𝑥 = - 𝑢 → ( - 𝑣 < 𝑥 ↔ - 𝑣 < - 𝑢 ) ) | |
| 97 | 96 | notbid | ⊢ ( 𝑥 = - 𝑢 → ( ¬ - 𝑣 < 𝑥 ↔ ¬ - 𝑣 < - 𝑢 ) ) |
| 98 | 97 | imbi2d | ⊢ ( 𝑥 = - 𝑢 → ( ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ↔ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < - 𝑢 ) ) ) |
| 99 | 98 | ralbidv | ⊢ ( 𝑥 = - 𝑢 → ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < - 𝑢 ) ) ) |
| 100 | breq1 | ⊢ ( 𝑥 = - 𝑢 → ( 𝑥 < - 𝑣 ↔ - 𝑢 < - 𝑣 ) ) | |
| 101 | 100 | imbi1d | ⊢ ( 𝑥 = - 𝑢 → ( ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ↔ ( - 𝑢 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) |
| 102 | 101 | ralbidv | ⊢ ( 𝑥 = - 𝑢 → ( ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ↔ ∀ 𝑣 ∈ ℝ ( - 𝑢 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) |
| 103 | 99 102 | anbi12d | ⊢ ( 𝑥 = - 𝑢 → ( ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ∧ ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ↔ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < - 𝑢 ) ∧ ∀ 𝑣 ∈ ℝ ( - 𝑢 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) ) |
| 104 | 31 32 103 | rexxfr | ⊢ ( ∃ 𝑥 ∈ ℝ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ∧ ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ↔ ∃ 𝑢 ∈ ℝ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < - 𝑢 ) ∧ ∀ 𝑣 ∈ ℝ ( - 𝑢 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) |
| 105 | 39 | imbi1i | ⊢ ( ( 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } → ¬ 𝑢 < 𝑣 ) ↔ ( ( 𝑣 ∈ ℝ ∧ - 𝑣 ∈ 𝐴 ) → ¬ 𝑢 < 𝑣 ) ) |
| 106 | impexp | ⊢ ( ( ( 𝑣 ∈ ℝ ∧ - 𝑣 ∈ 𝐴 ) → ¬ 𝑢 < 𝑣 ) ↔ ( 𝑣 ∈ ℝ → ( - 𝑣 ∈ 𝐴 → ¬ 𝑢 < 𝑣 ) ) ) | |
| 107 | 105 106 | bitri | ⊢ ( ( 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } → ¬ 𝑢 < 𝑣 ) ↔ ( 𝑣 ∈ ℝ → ( - 𝑣 ∈ 𝐴 → ¬ 𝑢 < 𝑣 ) ) ) |
| 108 | 107 | albii | ⊢ ( ∀ 𝑣 ( 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } → ¬ 𝑢 < 𝑣 ) ↔ ∀ 𝑣 ( 𝑣 ∈ ℝ → ( - 𝑣 ∈ 𝐴 → ¬ 𝑢 < 𝑣 ) ) ) |
| 109 | df-ral | ⊢ ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ↔ ∀ 𝑣 ( 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } → ¬ 𝑢 < 𝑣 ) ) | |
| 110 | df-ral | ⊢ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ 𝑢 < 𝑣 ) ↔ ∀ 𝑣 ( 𝑣 ∈ ℝ → ( - 𝑣 ∈ 𝐴 → ¬ 𝑢 < 𝑣 ) ) ) | |
| 111 | 108 109 110 | 3bitr4ri | ⊢ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ 𝑢 < 𝑣 ) ↔ ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ) |
| 112 | ltneg | ⊢ ( ( 𝑢 ∈ ℝ ∧ 𝑣 ∈ ℝ ) → ( 𝑢 < 𝑣 ↔ - 𝑣 < - 𝑢 ) ) | |
| 113 | 112 | notbid | ⊢ ( ( 𝑢 ∈ ℝ ∧ 𝑣 ∈ ℝ ) → ( ¬ 𝑢 < 𝑣 ↔ ¬ - 𝑣 < - 𝑢 ) ) |
| 114 | 113 | imbi2d | ⊢ ( ( 𝑢 ∈ ℝ ∧ 𝑣 ∈ ℝ ) → ( ( - 𝑣 ∈ 𝐴 → ¬ 𝑢 < 𝑣 ) ↔ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < - 𝑢 ) ) ) |
| 115 | 114 | ralbidva | ⊢ ( 𝑢 ∈ ℝ → ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ 𝑢 < 𝑣 ) ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < - 𝑢 ) ) ) |
| 116 | 111 115 | bitr3id | ⊢ ( 𝑢 ∈ ℝ → ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ↔ ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < - 𝑢 ) ) ) |
| 117 | ltneg | ⊢ ( ( 𝑣 ∈ ℝ ∧ 𝑢 ∈ ℝ ) → ( 𝑣 < 𝑢 ↔ - 𝑢 < - 𝑣 ) ) | |
| 118 | 117 | ancoms | ⊢ ( ( 𝑢 ∈ ℝ ∧ 𝑣 ∈ ℝ ) → ( 𝑣 < 𝑢 ↔ - 𝑢 < - 𝑣 ) ) |
| 119 | negeq | ⊢ ( 𝑤 = 𝑡 → - 𝑤 = - 𝑡 ) | |
| 120 | 119 | eleq1d | ⊢ ( 𝑤 = 𝑡 → ( - 𝑤 ∈ 𝐴 ↔ - 𝑡 ∈ 𝐴 ) ) |
| 121 | 120 | rexrab | ⊢ ( ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ↔ ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ 𝑣 < 𝑡 ) ) |
| 122 | ltneg | ⊢ ( ( 𝑣 ∈ ℝ ∧ 𝑡 ∈ ℝ ) → ( 𝑣 < 𝑡 ↔ - 𝑡 < - 𝑣 ) ) | |
| 123 | 122 | anbi2d | ⊢ ( ( 𝑣 ∈ ℝ ∧ 𝑡 ∈ ℝ ) → ( ( - 𝑡 ∈ 𝐴 ∧ 𝑣 < 𝑡 ) ↔ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) |
| 124 | 123 | rexbidva | ⊢ ( 𝑣 ∈ ℝ → ( ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ 𝑣 < 𝑡 ) ↔ ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) |
| 125 | 121 124 | bitrid | ⊢ ( 𝑣 ∈ ℝ → ( ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ↔ ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) |
| 126 | 125 | adantl | ⊢ ( ( 𝑢 ∈ ℝ ∧ 𝑣 ∈ ℝ ) → ( ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ↔ ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) |
| 127 | 118 126 | imbi12d | ⊢ ( ( 𝑢 ∈ ℝ ∧ 𝑣 ∈ ℝ ) → ( ( 𝑣 < 𝑢 → ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ) ↔ ( - 𝑢 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) |
| 128 | 127 | ralbidva | ⊢ ( 𝑢 ∈ ℝ → ( ∀ 𝑣 ∈ ℝ ( 𝑣 < 𝑢 → ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ) ↔ ∀ 𝑣 ∈ ℝ ( - 𝑢 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) |
| 129 | 116 128 | anbi12d | ⊢ ( 𝑢 ∈ ℝ → ( ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ∧ ∀ 𝑣 ∈ ℝ ( 𝑣 < 𝑢 → ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ) ) ↔ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < - 𝑢 ) ∧ ∀ 𝑣 ∈ ℝ ( - 𝑢 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) ) |
| 130 | 129 | rexbiia | ⊢ ( ∃ 𝑢 ∈ ℝ ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ∧ ∀ 𝑣 ∈ ℝ ( 𝑣 < 𝑢 → ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ) ) ↔ ∃ 𝑢 ∈ ℝ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < - 𝑢 ) ∧ ∀ 𝑣 ∈ ℝ ( - 𝑢 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ) |
| 131 | 104 130 | bitr4i | ⊢ ( ∃ 𝑥 ∈ ℝ ( ∀ 𝑣 ∈ ℝ ( - 𝑣 ∈ 𝐴 → ¬ - 𝑣 < 𝑥 ) ∧ ∀ 𝑣 ∈ ℝ ( 𝑥 < - 𝑣 → ∃ 𝑡 ∈ ℝ ( - 𝑡 ∈ 𝐴 ∧ - 𝑡 < - 𝑣 ) ) ) ↔ ∃ 𝑢 ∈ ℝ ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ∧ ∀ 𝑣 ∈ ℝ ( 𝑣 < 𝑢 → ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ) ) ) |
| 132 | 95 131 | bitrdi | ⊢ ( 𝐴 ⊆ ℝ → ( ∃ 𝑥 ∈ ℝ ( ∀ 𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥 ∧ ∀ 𝑦 ∈ ℝ ( 𝑥 < 𝑦 → ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ) ) ↔ ∃ 𝑢 ∈ ℝ ( ∀ 𝑣 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } ¬ 𝑢 < 𝑣 ∧ ∀ 𝑣 ∈ ℝ ( 𝑣 < 𝑢 → ∃ 𝑡 ∈ { 𝑤 ∈ ℝ ∣ - 𝑤 ∈ 𝐴 } 𝑣 < 𝑡 ) ) ) ) |
| 133 | 59 132 | sylibrd | ⊢ ( 𝐴 ⊆ ℝ → ( ( 𝐴 ≠ ∅ ∧ ∃ 𝑥 ∈ ℝ ∀ 𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ) → ∃ 𝑥 ∈ ℝ ( ∀ 𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥 ∧ ∀ 𝑦 ∈ ℝ ( 𝑥 < 𝑦 → ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ) ) ) ) |
| 134 | 133 | 3impib | ⊢ ( ( 𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅ ∧ ∃ 𝑥 ∈ ℝ ∀ 𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ) → ∃ 𝑥 ∈ ℝ ( ∀ 𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥 ∧ ∀ 𝑦 ∈ ℝ ( 𝑥 < 𝑦 → ∃ 𝑧 ∈ 𝐴 𝑧 < 𝑦 ) ) ) |