Description: Define division over extended real numbers. (Contributed by Thierry Arnoux, 17-Dec-2016)
Ref | Expression | ||
---|---|---|---|
Assertion | df-xdiv | ⊢ /𝑒 = ( 𝑥 ∈ ℝ* , 𝑦 ∈ ( ℝ ∖ { 0 } ) ↦ ( ℩ 𝑧 ∈ ℝ* ( 𝑦 ·e 𝑧 ) = 𝑥 ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
0 | cxdiv | ⊢ /𝑒 | |
1 | vx | ⊢ 𝑥 | |
2 | cxr | ⊢ ℝ* | |
3 | vy | ⊢ 𝑦 | |
4 | cr | ⊢ ℝ | |
5 | cc0 | ⊢ 0 | |
6 | 5 | csn | ⊢ { 0 } |
7 | 4 6 | cdif | ⊢ ( ℝ ∖ { 0 } ) |
8 | vz | ⊢ 𝑧 | |
9 | 3 | cv | ⊢ 𝑦 |
10 | cxmu | ⊢ ·e | |
11 | 8 | cv | ⊢ 𝑧 |
12 | 9 11 10 | co | ⊢ ( 𝑦 ·e 𝑧 ) |
13 | 1 | cv | ⊢ 𝑥 |
14 | 12 13 | wceq | ⊢ ( 𝑦 ·e 𝑧 ) = 𝑥 |
15 | 14 8 2 | crio | ⊢ ( ℩ 𝑧 ∈ ℝ* ( 𝑦 ·e 𝑧 ) = 𝑥 ) |
16 | 1 3 2 7 15 | cmpo | ⊢ ( 𝑥 ∈ ℝ* , 𝑦 ∈ ( ℝ ∖ { 0 } ) ↦ ( ℩ 𝑧 ∈ ℝ* ( 𝑦 ·e 𝑧 ) = 𝑥 ) ) |
17 | 0 16 | wceq | ⊢ /𝑒 = ( 𝑥 ∈ ℝ* , 𝑦 ∈ ( ℝ ∖ { 0 } ) ↦ ( ℩ 𝑧 ∈ ℝ* ( 𝑦 ·e 𝑧 ) = 𝑥 ) ) |