Detailed syntax breakdown of Definition df-ico
| Step | Hyp | Ref
 | Expression | 
| 1 |   | cico 9965 | 
. 2
class
[,) | 
| 2 |   | vx | 
. . 3
setvar 𝑥 | 
| 3 |   | vy | 
. . 3
setvar 𝑦 | 
| 4 |   | cxr 8060 | 
. . 3
class
ℝ* | 
| 5 | 2 | cv 1363 | 
. . . . . 6
class 𝑥 | 
| 6 |   | vz | 
. . . . . . 7
setvar 𝑧 | 
| 7 | 6 | cv 1363 | 
. . . . . 6
class 𝑧 | 
| 8 |   | cle 8062 | 
. . . . . 6
class 
≤ | 
| 9 | 5, 7, 8 | wbr 4033 | 
. . . . 5
wff 𝑥 ≤ 𝑧 | 
| 10 | 3 | cv 1363 | 
. . . . . 6
class 𝑦 | 
| 11 |   | clt 8061 | 
. . . . . 6
class 
< | 
| 12 | 7, 10, 11 | wbr 4033 | 
. . . . 5
wff 𝑧 < 𝑦 | 
| 13 | 9, 12 | wa 104 | 
. . . 4
wff (𝑥 ≤ 𝑧 ∧ 𝑧 < 𝑦) | 
| 14 | 13, 6, 4 | crab 2479 | 
. . 3
class {𝑧 ∈ ℝ*
∣ (𝑥 ≤ 𝑧 ∧ 𝑧 < 𝑦)} | 
| 15 | 2, 3, 4, 4, 14 | cmpo 5924 | 
. 2
class (𝑥 ∈ ℝ*,
𝑦 ∈
ℝ* ↦ {𝑧 ∈ ℝ* ∣ (𝑥 ≤ 𝑧 ∧ 𝑧 < 𝑦)}) | 
| 16 | 1, 15 | wceq 1364 | 
1
wff [,) =
(𝑥 ∈
ℝ*, 𝑦
∈ ℝ* ↦ {𝑧 ∈ ℝ* ∣ (𝑥 ≤ 𝑧 ∧ 𝑧 < 𝑦)}) |