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Description: Define the domain quotient predicate. (Read: the domain quotient of R is A .) If A and R are sets, the domain quotient binary relation and the domain quotient predicate are the same, see brdmqssqs . (Contributed by Peter Mazsa, 9-Aug-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-dmqs | |- ( R DomainQs A <-> ( dom R /. R ) = A ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cR | |- R |
|
| 1 | cA | |- A |
|
| 2 | 1 0 | wdmqs | |- R DomainQs A |
| 3 | 0 | cdm | |- dom R |
| 4 | 3 0 | cqs | |- ( dom R /. R ) |
| 5 | 4 1 | wceq | |- ( dom R /. R ) = A |
| 6 | 2 5 | wb | |- ( R DomainQs A <-> ( dom R /. R ) = A ) |