Metamath Proof Explorer


Theorem elin1d

Description: Elementhood in the first set of an intersection - deduction version. (Contributed by Thierry Arnoux, 3-May-2020)

Ref Expression
Hypothesis elin1d.1 φ X A B
Assertion elin1d φ X A

Proof

Step Hyp Ref Expression
1 elin1d.1 φ X A B
2 elinel1 X A B X A
3 1 2 syl φ X A