Description: Degenerated case 4 for edges: The set of indexed edges of a proper class is the empty set. (Contributed by AV, 12-Oct-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | iedgvalprc | |- ( C e/ _V -> ( iEdg ` C ) = (/) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-nel | |- ( C e/ _V <-> -. C e. _V ) |
|
2 | fvprc | |- ( -. C e. _V -> ( iEdg ` C ) = (/) ) |
|
3 | 1 2 | sylbi | |- ( C e/ _V -> ( iEdg ` C ) = (/) ) |