Detailed syntax breakdown of Definition df-fz
| Step | Hyp | Ref
 | Expression | 
| 1 |   | cfz 10083 | 
. 2
class
... | 
| 2 |   | vm | 
. . 3
setvar 𝑚 | 
| 3 |   | vn | 
. . 3
setvar 𝑛 | 
| 4 |   | cz 9326 | 
. . 3
class
ℤ | 
| 5 | 2 | cv 1363 | 
. . . . . 6
class 𝑚 | 
| 6 |   | vk | 
. . . . . . 7
setvar 𝑘 | 
| 7 | 6 | cv 1363 | 
. . . . . 6
class 𝑘 | 
| 8 |   | cle 8062 | 
. . . . . 6
class 
≤ | 
| 9 | 5, 7, 8 | wbr 4033 | 
. . . . 5
wff 𝑚 ≤ 𝑘 | 
| 10 | 3 | cv 1363 | 
. . . . . 6
class 𝑛 | 
| 11 | 7, 10, 8 | wbr 4033 | 
. . . . 5
wff 𝑘 ≤ 𝑛 | 
| 12 | 9, 11 | wa 104 | 
. . . 4
wff (𝑚 ≤ 𝑘 ∧ 𝑘 ≤ 𝑛) | 
| 13 | 12, 6, 4 | crab 2479 | 
. . 3
class {𝑘 ∈ ℤ ∣ (𝑚 ≤ 𝑘 ∧ 𝑘 ≤ 𝑛)} | 
| 14 | 2, 3, 4, 4, 13 | cmpo 5924 | 
. 2
class (𝑚 ∈ ℤ, 𝑛 ∈ ℤ ↦ {𝑘 ∈ ℤ ∣ (𝑚 ≤ 𝑘 ∧ 𝑘 ≤ 𝑛)}) | 
| 15 | 1, 14 | wceq 1364 | 
1
wff ... =
(𝑚 ∈ ℤ, 𝑛 ∈ ℤ ↦ {𝑘 ∈ ℤ ∣ (𝑚 ≤ 𝑘 ∧ 𝑘 ≤ 𝑛)}) |