Description: If A belongs to a part of C , then A belongs to C . (Contributed by FL, 3-Aug-2009)
Ref | Expression | ||
---|---|---|---|
Assertion | elelpwi | ⊢ ( ( 𝐴 ∈ 𝐵 ∧ 𝐵 ∈ 𝒫 𝐶 ) → 𝐴 ∈ 𝐶 ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elpwi | ⊢ ( 𝐵 ∈ 𝒫 𝐶 → 𝐵 ⊆ 𝐶 ) | |
2 | 1 | sseld | ⊢ ( 𝐵 ∈ 𝒫 𝐶 → ( 𝐴 ∈ 𝐵 → 𝐴 ∈ 𝐶 ) ) |
3 | 2 | impcom | ⊢ ( ( 𝐴 ∈ 𝐵 ∧ 𝐵 ∈ 𝒫 𝐶 ) → 𝐴 ∈ 𝐶 ) |