Metamath Proof Explorer


Theorem msubrsub

Description: A substitution applied to an expression. (Contributed by Mario Carneiro, 18-Jul-2016)

Ref Expression
Hypotheses msubffval.v
|- V = ( mVR ` T )
msubffval.r
|- R = ( mREx ` T )
msubffval.s
|- S = ( mSubst ` T )
msubffval.e
|- E = ( mEx ` T )
msubffval.o
|- O = ( mRSubst ` T )
Assertion msubrsub
|- ( ( F : A --> R /\ A C_ V /\ X e. E ) -> ( 2nd ` ( ( S ` F ) ` X ) ) = ( ( O ` F ) ` ( 2nd ` X ) ) )

Proof

Step Hyp Ref Expression
1 msubffval.v
 |-  V = ( mVR ` T )
2 msubffval.r
 |-  R = ( mREx ` T )
3 msubffval.s
 |-  S = ( mSubst ` T )
4 msubffval.e
 |-  E = ( mEx ` T )
5 msubffval.o
 |-  O = ( mRSubst ` T )
6 1 2 3 4 5 msubval
 |-  ( ( F : A --> R /\ A C_ V /\ X e. E ) -> ( ( S ` F ) ` X ) = <. ( 1st ` X ) , ( ( O ` F ) ` ( 2nd ` X ) ) >. )
7 fvex
 |-  ( 1st ` X ) e. _V
8 fvex
 |-  ( ( O ` F ) ` ( 2nd ` X ) ) e. _V
9 7 8 op2ndd
 |-  ( ( ( S ` F ) ` X ) = <. ( 1st ` X ) , ( ( O ` F ) ` ( 2nd ` X ) ) >. -> ( 2nd ` ( ( S ` F ) ` X ) ) = ( ( O ` F ) ` ( 2nd ` X ) ) )
10 6 9 syl
 |-  ( ( F : A --> R /\ A C_ V /\ X e. E ) -> ( 2nd ` ( ( S ` F ) ` X ) ) = ( ( O ` F ) ` ( 2nd ` X ) ) )