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Description: Define the _lcm function on a set of integers. (Contributed by AV, 21-Aug-2020) (Revised by AV, 16-Sep-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-lcmf | ⊢ lcm = ( 𝑧 ∈ 𝒫 ℤ ↦ if ( 0 ∈ 𝑧 , 0 , inf ( { 𝑛 ∈ ℕ ∣ ∀ 𝑚 ∈ 𝑧 𝑚 ∥ 𝑛 } , ℝ , < ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | clcmf | ⊢ lcm | |
| 1 | vz | ⊢ 𝑧 | |
| 2 | cz | ⊢ ℤ | |
| 3 | 2 | cpw | ⊢ 𝒫 ℤ |
| 4 | cc0 | ⊢ 0 | |
| 5 | 1 | cv | ⊢ 𝑧 |
| 6 | 4 5 | wcel | ⊢ 0 ∈ 𝑧 |
| 7 | vn | ⊢ 𝑛 | |
| 8 | cn | ⊢ ℕ | |
| 9 | vm | ⊢ 𝑚 | |
| 10 | 9 | cv | ⊢ 𝑚 |
| 11 | cdvds | ⊢ ∥ | |
| 12 | 7 | cv | ⊢ 𝑛 |
| 13 | 10 12 11 | wbr | ⊢ 𝑚 ∥ 𝑛 |
| 14 | 13 9 5 | wral | ⊢ ∀ 𝑚 ∈ 𝑧 𝑚 ∥ 𝑛 |
| 15 | 14 7 8 | crab | ⊢ { 𝑛 ∈ ℕ ∣ ∀ 𝑚 ∈ 𝑧 𝑚 ∥ 𝑛 } |
| 16 | cr | ⊢ ℝ | |
| 17 | clt | ⊢ < | |
| 18 | 15 16 17 | cinf | ⊢ inf ( { 𝑛 ∈ ℕ ∣ ∀ 𝑚 ∈ 𝑧 𝑚 ∥ 𝑛 } , ℝ , < ) |
| 19 | 6 4 18 | cif | ⊢ if ( 0 ∈ 𝑧 , 0 , inf ( { 𝑛 ∈ ℕ ∣ ∀ 𝑚 ∈ 𝑧 𝑚 ∥ 𝑛 } , ℝ , < ) ) |
| 20 | 1 3 19 | cmpt | ⊢ ( 𝑧 ∈ 𝒫 ℤ ↦ if ( 0 ∈ 𝑧 , 0 , inf ( { 𝑛 ∈ ℕ ∣ ∀ 𝑚 ∈ 𝑧 𝑚 ∥ 𝑛 } , ℝ , < ) ) ) |
| 21 | 0 20 | wceq | ⊢ lcm = ( 𝑧 ∈ 𝒫 ℤ ↦ if ( 0 ∈ 𝑧 , 0 , inf ( { 𝑛 ∈ ℕ ∣ ∀ 𝑚 ∈ 𝑧 𝑚 ∥ 𝑛 } , ℝ , < ) ) ) |