Proof of Theorem eluz2
Step | Hyp | Ref
| Expression |
1 | | eluzel2 12251 |
. 2
⊢ (𝑁 ∈
(ℤ≥‘𝑀) → 𝑀 ∈ ℤ) |
2 | | simp1 1132 |
. 2
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁) → 𝑀 ∈ ℤ) |
3 | | eluz1 12250 |
. . . 4
⊢ (𝑀 ∈ ℤ → (𝑁 ∈
(ℤ≥‘𝑀) ↔ (𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁))) |
4 | | ibar 531 |
. . . 4
⊢ (𝑀 ∈ ℤ → ((𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁) ↔ (𝑀 ∈ ℤ ∧ (𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁)))) |
5 | 3, 4 | bitrd 281 |
. . 3
⊢ (𝑀 ∈ ℤ → (𝑁 ∈
(ℤ≥‘𝑀) ↔ (𝑀 ∈ ℤ ∧ (𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁)))) |
6 | | 3anass 1091 |
. . 3
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁) ↔ (𝑀 ∈ ℤ ∧ (𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁))) |
7 | 5, 6 | syl6bbr 291 |
. 2
⊢ (𝑀 ∈ ℤ → (𝑁 ∈
(ℤ≥‘𝑀) ↔ (𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁))) |
8 | 1, 2, 7 | pm5.21nii 382 |
1
⊢ (𝑁 ∈
(ℤ≥‘𝑀) ↔ (𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁)) |