Description: A class cannot be an element of one of its elements. (Contributed by AV, 14-Jun-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | elnotel | |- ( A e. B -> -. B e. A ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | en2lp | |- -. ( A e. B /\ B e. A ) |
|
2 | 1 | imnani | |- ( A e. B -> -. B e. A ) |