Metamath Proof Explorer


Theorem inteqd

Description: Equality deduction for class intersection. (Contributed by NM, 2-Sep-2003)

Ref Expression
Hypothesis inteqd.1 φ A = B
Assertion inteqd φ A = B

Proof

Step Hyp Ref Expression
1 inteqd.1 φ A = B
2 inteq A = B A = B
3 1 2 syl φ A = B