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Description: Element of the domain of the range product with restricted converse epsilon relation. (Contributed by Peter Mazsa, 23-Nov-2025)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | eldmxrncnvepres | |- ( B e. V -> ( B e. dom ( R |X. ( `' _E |` A ) ) <-> ( B e. A /\ B =/= (/) /\ [ B ] R =/= (/) ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | eldmres3 | |- ( B e. V -> ( B e. dom ( R |` A ) <-> ( B e. A /\ [ B ] R =/= (/) ) ) ) |
|
| 2 | 1 | anbi1d | |- ( B e. V -> ( ( B e. dom ( R |` A ) /\ B =/= (/) ) <-> ( ( B e. A /\ [ B ] R =/= (/) ) /\ B =/= (/) ) ) ) |
| 3 | dmxrncnvepres | |- dom ( R |X. ( `' _E |` A ) ) = ( dom ( R |` A ) \ { (/) } ) |
|
| 4 | 3 | eleq2i | |- ( B e. dom ( R |X. ( `' _E |` A ) ) <-> B e. ( dom ( R |` A ) \ { (/) } ) ) |
| 5 | eldifsn | |- ( B e. ( dom ( R |` A ) \ { (/) } ) <-> ( B e. dom ( R |` A ) /\ B =/= (/) ) ) |
|
| 6 | 4 5 | bitri | |- ( B e. dom ( R |X. ( `' _E |` A ) ) <-> ( B e. dom ( R |` A ) /\ B =/= (/) ) ) |
| 7 | 3anan32 | |- ( ( B e. A /\ B =/= (/) /\ [ B ] R =/= (/) ) <-> ( ( B e. A /\ [ B ] R =/= (/) ) /\ B =/= (/) ) ) |
|
| 8 | 2 6 7 | 3bitr4g | |- ( B e. V -> ( B e. dom ( R |X. ( `' _E |` A ) ) <-> ( B e. A /\ B =/= (/) /\ [ B ] R =/= (/) ) ) ) |