Description: Subclass relation for a restricted class. (Contributed by NM, 19-Mar-1997)
Ref | Expression | ||
---|---|---|---|
Assertion | ssrab2 | ⊢ { 𝑥 ∈ 𝐴 ∣ 𝜑 } ⊆ 𝐴 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-rab | ⊢ { 𝑥 ∈ 𝐴 ∣ 𝜑 } = { 𝑥 ∣ ( 𝑥 ∈ 𝐴 ∧ 𝜑 ) } | |
2 | ssab2 | ⊢ { 𝑥 ∣ ( 𝑥 ∈ 𝐴 ∧ 𝜑 ) } ⊆ 𝐴 | |
3 | 1 2 | eqsstri | ⊢ { 𝑥 ∈ 𝐴 ∣ 𝜑 } ⊆ 𝐴 |