Description: A class cannot be an element of one of its elements. (Contributed by AV, 14-Jun-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | elnotel | ⊢ ( 𝐴 ∈ 𝐵 → ¬ 𝐵 ∈ 𝐴 ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | en2lp | ⊢ ¬ ( 𝐴 ∈ 𝐵 ∧ 𝐵 ∈ 𝐴 ) | |
2 | 1 | imnani | ⊢ ( 𝐴 ∈ 𝐵 → ¬ 𝐵 ∈ 𝐴 ) |