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Description: Binary equivalence relation with natural domain, see the comment of df-ers . (Contributed by Peter Mazsa, 23-Jul-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | brers | ⊢ ( 𝐴 ∈ 𝑉 → ( 𝑅 Ers 𝐴 ↔ ( 𝑅 ∈ EqvRels ∧ 𝑅 DomainQss 𝐴 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-ers | ⊢ Ers = ( DomainQss ↾ EqvRels ) | |
| 2 | 1 | eqres | ⊢ ( 𝐴 ∈ 𝑉 → ( 𝑅 Ers 𝐴 ↔ ( 𝑅 ∈ EqvRels ∧ 𝑅 DomainQss 𝐴 ) ) ) |