Metamath Proof Explorer


Theorem ipval

Description: Value of the inner product. The definition is meaningful for normed complex vector spaces that are also inner product spaces, i.e. satisfy the parallelogram law, although for convenience we define it for any normed complex vector space. The vector (group) addition operation is G , the scalar product is S , the norm is N , and the set of vectors is X . Equation 6.45 of Ponnusamy p. 361. (Contributed by NM, 31-Jan-2007) (Revised by Mario Carneiro, 16-Nov-2013) (New usage is discouraged.)

Ref Expression
Hypotheses dipfval.1 𝑋 = ( BaseSet ‘ 𝑈 )
dipfval.2 𝐺 = ( +𝑣𝑈 )
dipfval.4 𝑆 = ( ·𝑠OLD𝑈 )
dipfval.6 𝑁 = ( normCV𝑈 )
dipfval.7 𝑃 = ( ·𝑖OLD𝑈 )
Assertion ipval ( ( 𝑈 ∈ NrmCVec ∧ 𝐴𝑋𝐵𝑋 ) → ( 𝐴 𝑃 𝐵 ) = ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) ↑ 2 ) ) / 4 ) )

Proof

Step Hyp Ref Expression
1 dipfval.1 𝑋 = ( BaseSet ‘ 𝑈 )
2 dipfval.2 𝐺 = ( +𝑣𝑈 )
3 dipfval.4 𝑆 = ( ·𝑠OLD𝑈 )
4 dipfval.6 𝑁 = ( normCV𝑈 )
5 dipfval.7 𝑃 = ( ·𝑖OLD𝑈 )
6 1 2 3 4 5 dipfval ( 𝑈 ∈ NrmCVec → 𝑃 = ( 𝑥𝑋 , 𝑦𝑋 ↦ ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) / 4 ) ) )
7 6 oveqd ( 𝑈 ∈ NrmCVec → ( 𝐴 𝑃 𝐵 ) = ( 𝐴 ( 𝑥𝑋 , 𝑦𝑋 ↦ ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) / 4 ) ) 𝐵 ) )
8 fvoveq1 ( 𝑥 = 𝐴 → ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) = ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) )
9 8 oveq1d ( 𝑥 = 𝐴 → ( ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) = ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) )
10 9 oveq2d ( 𝑥 = 𝐴 → ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) = ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) )
11 10 sumeq2sdv ( 𝑥 = 𝐴 → Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) = Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) )
12 11 oveq1d ( 𝑥 = 𝐴 → ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) / 4 ) = ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) / 4 ) )
13 oveq2 ( 𝑦 = 𝐵 → ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) = ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) )
14 13 oveq2d ( 𝑦 = 𝐵 → ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) = ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) )
15 14 fveq2d ( 𝑦 = 𝐵 → ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) = ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) )
16 15 oveq1d ( 𝑦 = 𝐵 → ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) = ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) ↑ 2 ) )
17 16 oveq2d ( 𝑦 = 𝐵 → ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) = ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) ↑ 2 ) ) )
18 17 sumeq2sdv ( 𝑦 = 𝐵 → Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) = Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) ↑ 2 ) ) )
19 18 oveq1d ( 𝑦 = 𝐵 → ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) / 4 ) = ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) ↑ 2 ) ) / 4 ) )
20 eqid ( 𝑥𝑋 , 𝑦𝑋 ↦ ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) / 4 ) ) = ( 𝑥𝑋 , 𝑦𝑋 ↦ ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) / 4 ) )
21 ovex ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) ↑ 2 ) ) / 4 ) ∈ V
22 12 19 20 21 ovmpo ( ( 𝐴𝑋𝐵𝑋 ) → ( 𝐴 ( 𝑥𝑋 , 𝑦𝑋 ↦ ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝑥 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝑦 ) ) ) ↑ 2 ) ) / 4 ) ) 𝐵 ) = ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) ↑ 2 ) ) / 4 ) )
23 7 22 sylan9eq ( ( 𝑈 ∈ NrmCVec ∧ ( 𝐴𝑋𝐵𝑋 ) ) → ( 𝐴 𝑃 𝐵 ) = ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) ↑ 2 ) ) / 4 ) )
24 23 3impb ( ( 𝑈 ∈ NrmCVec ∧ 𝐴𝑋𝐵𝑋 ) → ( 𝐴 𝑃 𝐵 ) = ( Σ 𝑘 ∈ ( 1 ... 4 ) ( ( i ↑ 𝑘 ) · ( ( 𝑁 ‘ ( 𝐴 𝐺 ( ( i ↑ 𝑘 ) 𝑆 𝐵 ) ) ) ↑ 2 ) ) / 4 ) )