Metamath Proof Explorer


Theorem kbfval

Description: The outer product of two vectors, expressed as | A >. <. B | in Dirac notation. See df-kb . (Contributed by NM, 15-May-2006) (Revised by Mario Carneiro, 23-Aug-2014) (New usage is discouraged.)

Ref Expression
Assertion kbfval ( ( 𝐴 ∈ ℋ ∧ 𝐵 ∈ ℋ ) → ( 𝐴 ketbra 𝐵 ) = ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝐵 ) · 𝐴 ) ) )

Proof

Step Hyp Ref Expression
1 oveq2 ( 𝑦 = 𝐴 → ( ( 𝑥 ·ih 𝑧 ) · 𝑦 ) = ( ( 𝑥 ·ih 𝑧 ) · 𝐴 ) )
2 1 mpteq2dv ( 𝑦 = 𝐴 → ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝑧 ) · 𝑦 ) ) = ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝑧 ) · 𝐴 ) ) )
3 oveq2 ( 𝑧 = 𝐵 → ( 𝑥 ·ih 𝑧 ) = ( 𝑥 ·ih 𝐵 ) )
4 3 oveq1d ( 𝑧 = 𝐵 → ( ( 𝑥 ·ih 𝑧 ) · 𝐴 ) = ( ( 𝑥 ·ih 𝐵 ) · 𝐴 ) )
5 4 mpteq2dv ( 𝑧 = 𝐵 → ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝑧 ) · 𝐴 ) ) = ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝐵 ) · 𝐴 ) ) )
6 df-kb ketbra = ( 𝑦 ∈ ℋ , 𝑧 ∈ ℋ ↦ ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝑧 ) · 𝑦 ) ) )
7 ax-hilex ℋ ∈ V
8 7 mptex ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝐵 ) · 𝐴 ) ) ∈ V
9 2 5 6 8 ovmpo ( ( 𝐴 ∈ ℋ ∧ 𝐵 ∈ ℋ ) → ( 𝐴 ketbra 𝐵 ) = ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝐵 ) · 𝐴 ) ) )