Description: Shorter proof of inrab . (Contributed by BJ, 21-Apr-2019) (Proof modification is discouraged.)
Ref | Expression | ||
---|---|---|---|
Assertion | bj-inrab2 | ⊢ ( { 𝑥 ∈ 𝐴 ∣ 𝜑 } ∩ { 𝑥 ∈ 𝐴 ∣ 𝜓 } ) = { 𝑥 ∈ 𝐴 ∣ ( 𝜑 ∧ 𝜓 ) } |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | bj-inrab | ⊢ ( { 𝑥 ∈ 𝐴 ∣ 𝜑 } ∩ { 𝑥 ∈ 𝐴 ∣ 𝜓 } ) = { 𝑥 ∈ ( 𝐴 ∩ 𝐴 ) ∣ ( 𝜑 ∧ 𝜓 ) } | |
2 | nfv | ⊢ Ⅎ 𝑥 ⊤ | |
3 | inidm | ⊢ ( 𝐴 ∩ 𝐴 ) = 𝐴 | |
4 | 3 | a1i | ⊢ ( ⊤ → ( 𝐴 ∩ 𝐴 ) = 𝐴 ) |
5 | 2 4 | bj-rabeqd | ⊢ ( ⊤ → { 𝑥 ∈ ( 𝐴 ∩ 𝐴 ) ∣ ( 𝜑 ∧ 𝜓 ) } = { 𝑥 ∈ 𝐴 ∣ ( 𝜑 ∧ 𝜓 ) } ) |
6 | 5 | mptru | ⊢ { 𝑥 ∈ ( 𝐴 ∩ 𝐴 ) ∣ ( 𝜑 ∧ 𝜓 ) } = { 𝑥 ∈ 𝐴 ∣ ( 𝜑 ∧ 𝜓 ) } |
7 | 1 6 | eqtri | ⊢ ( { 𝑥 ∈ 𝐴 ∣ 𝜑 } ∩ { 𝑥 ∈ 𝐴 ∣ 𝜓 } ) = { 𝑥 ∈ 𝐴 ∣ ( 𝜑 ∧ 𝜓 ) } |