This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.
Description: Define the class of domain quotients. Domain quotients are pairs of sets, typically a relation and a set, where the quotient (see df-qs ) of the relation on its domain is equal to the set. See comments of df-ers for the motivation for this definition. (Contributed by Peter Mazsa, 16-Apr-2019)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-dmqss | ⊢ DomainQss = { 〈 𝑥 , 𝑦 〉 ∣ ( dom 𝑥 / 𝑥 ) = 𝑦 } |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cdmqss | ⊢ DomainQss | |
| 1 | vx | ⊢ 𝑥 | |
| 2 | vy | ⊢ 𝑦 | |
| 3 | 1 | cv | ⊢ 𝑥 |
| 4 | 3 | cdm | ⊢ dom 𝑥 |
| 5 | 4 3 | cqs | ⊢ ( dom 𝑥 / 𝑥 ) |
| 6 | 2 | cv | ⊢ 𝑦 |
| 7 | 5 6 | wceq | ⊢ ( dom 𝑥 / 𝑥 ) = 𝑦 |
| 8 | 7 1 2 | copab | ⊢ { 〈 𝑥 , 𝑦 〉 ∣ ( dom 𝑥 / 𝑥 ) = 𝑦 } |
| 9 | 0 8 | wceq | ⊢ DomainQss = { 〈 𝑥 , 𝑦 〉 ∣ ( dom 𝑥 / 𝑥 ) = 𝑦 } |