Metamath Proof Explorer


Theorem iuneq12d

Description: Equality deduction for indexed union, deduction version. (Contributed by Drahflow, 22-Oct-2015)

Ref Expression
Hypotheses iuneq1d.1
|- ( ph -> A = B )
iuneq12d.2
|- ( ph -> C = D )
Assertion iuneq12d
|- ( ph -> U_ x e. A C = U_ x e. B D )

Proof

Step Hyp Ref Expression
1 iuneq1d.1
 |-  ( ph -> A = B )
2 iuneq12d.2
 |-  ( ph -> C = D )
3 1 iuneq1d
 |-  ( ph -> U_ x e. A C = U_ x e. B C )
4 2 adantr
 |-  ( ( ph /\ x e. B ) -> C = D )
5 4 iuneq2dv
 |-  ( ph -> U_ x e. B C = U_ x e. B D )
6 3 5 eqtrd
 |-  ( ph -> U_ x e. A C = U_ x e. B D )