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Quantifier-free definitions
pprodcnveq
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pprodss4v
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Theorem
pprodcnveq
Description:
A converse law for parallel product.
(Contributed by
Scott Fenton
, 3-May-2014)
Ref
Expression
Assertion
pprodcnveq
⊢
pprod
R
S
=
pprod
R
-1
S
-1
-1
Proof
Step
Hyp
Ref
Expression
1
dfpprod2
⊢
pprod
R
S
=
1
st
↾
V
×
V
-1
∘
R
∘
1
st
↾
V
×
V
∩
2
nd
↾
V
×
V
-1
∘
S
∘
2
nd
↾
V
×
V
2
dfpprod2
⊢
pprod
R
-1
S
-1
=
1
st
↾
V
×
V
-1
∘
R
-1
∘
1
st
↾
V
×
V
∩
2
nd
↾
V
×
V
-1
∘
S
-1
∘
2
nd
↾
V
×
V
3
2
cnveqi
⊢
pprod
R
-1
S
-1
-1
=
1
st
↾
V
×
V
-1
∘
R
-1
∘
1
st
↾
V
×
V
∩
2
nd
↾
V
×
V
-1
∘
S
-1
∘
2
nd
↾
V
×
V
-1
4
cnvin
⊢
1
st
↾
V
×
V
-1
∘
R
-1
∘
1
st
↾
V
×
V
∩
2
nd
↾
V
×
V
-1
∘
S
-1
∘
2
nd
↾
V
×
V
-1
=
1
st
↾
V
×
V
-1
∘
R
-1
∘
1
st
↾
V
×
V
-1
∩
2
nd
↾
V
×
V
-1
∘
S
-1
∘
2
nd
↾
V
×
V
-1
5
cnvco1
⊢
1
st
↾
V
×
V
-1
∘
R
-1
∘
1
st
↾
V
×
V
-1
=
R
-1
∘
1
st
↾
V
×
V
-1
∘
1
st
↾
V
×
V
6
cnvco1
⊢
R
-1
∘
1
st
↾
V
×
V
-1
=
1
st
↾
V
×
V
-1
∘
R
7
6
coeq1i
⊢
R
-1
∘
1
st
↾
V
×
V
-1
∘
1
st
↾
V
×
V
=
1
st
↾
V
×
V
-1
∘
R
∘
1
st
↾
V
×
V
8
coass
⊢
1
st
↾
V
×
V
-1
∘
R
∘
1
st
↾
V
×
V
=
1
st
↾
V
×
V
-1
∘
R
∘
1
st
↾
V
×
V
9
5
7
8
3eqtri
⊢
1
st
↾
V
×
V
-1
∘
R
-1
∘
1
st
↾
V
×
V
-1
=
1
st
↾
V
×
V
-1
∘
R
∘
1
st
↾
V
×
V
10
cnvco1
⊢
2
nd
↾
V
×
V
-1
∘
S
-1
∘
2
nd
↾
V
×
V
-1
=
S
-1
∘
2
nd
↾
V
×
V
-1
∘
2
nd
↾
V
×
V
11
cnvco1
⊢
S
-1
∘
2
nd
↾
V
×
V
-1
=
2
nd
↾
V
×
V
-1
∘
S
12
11
coeq1i
⊢
S
-1
∘
2
nd
↾
V
×
V
-1
∘
2
nd
↾
V
×
V
=
2
nd
↾
V
×
V
-1
∘
S
∘
2
nd
↾
V
×
V
13
coass
⊢
2
nd
↾
V
×
V
-1
∘
S
∘
2
nd
↾
V
×
V
=
2
nd
↾
V
×
V
-1
∘
S
∘
2
nd
↾
V
×
V
14
10
12
13
3eqtri
⊢
2
nd
↾
V
×
V
-1
∘
S
-1
∘
2
nd
↾
V
×
V
-1
=
2
nd
↾
V
×
V
-1
∘
S
∘
2
nd
↾
V
×
V
15
9
14
ineq12i
⊢
1
st
↾
V
×
V
-1
∘
R
-1
∘
1
st
↾
V
×
V
-1
∩
2
nd
↾
V
×
V
-1
∘
S
-1
∘
2
nd
↾
V
×
V
-1
=
1
st
↾
V
×
V
-1
∘
R
∘
1
st
↾
V
×
V
∩
2
nd
↾
V
×
V
-1
∘
S
∘
2
nd
↾
V
×
V
16
3
4
15
3eqtri
⊢
pprod
R
-1
S
-1
-1
=
1
st
↾
V
×
V
-1
∘
R
∘
1
st
↾
V
×
V
∩
2
nd
↾
V
×
V
-1
∘
S
∘
2
nd
↾
V
×
V
17
1
16
eqtr4i
⊢
pprod
R
S
=
pprod
R
-1
S
-1
-1