Description: Proper classes are not related via any relation. (Contributed by AV, 29-Oct-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | nprrel12.1 | |- Rel R |
|
| Assertion | nprrel12 | |- ( -. ( A e. _V /\ B e. _V ) -> -. A R B ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nprrel12.1 | |- Rel R |
|
| 2 | 1 | brrelex12i | |- ( A R B -> ( A e. _V /\ B e. _V ) ) |
| 3 | 2 | con3i | |- ( -. ( A e. _V /\ B e. _V ) -> -. A R B ) |