Metamath Proof Explorer


Theorem msubval

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 msubval F : A R A V X E S F X = 1 st X O F 2 nd 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 msubfval F : A R A V S F = e E 1 st e O F 2 nd e
7 6 3adant3 F : A R A V X E S F = e E 1 st e O F 2 nd e
8 simpr F : A R A V X E e = X e = X
9 8 fveq2d F : A R A V X E e = X 1 st e = 1 st X
10 8 fveq2d F : A R A V X E e = X 2 nd e = 2 nd X
11 10 fveq2d F : A R A V X E e = X O F 2 nd e = O F 2 nd X
12 9 11 opeq12d F : A R A V X E e = X 1 st e O F 2 nd e = 1 st X O F 2 nd X
13 simp3 F : A R A V X E X E
14 opex 1 st X O F 2 nd X V
15 14 a1i F : A R A V X E 1 st X O F 2 nd X V
16 7 12 13 15 fvmptd F : A R A V X E S F X = 1 st X O F 2 nd X