Step |
Hyp |
Ref |
Expression |
1 |
|
kbfval |
⊢ ( ( 𝐴 ∈ ℋ ∧ 𝐵 ∈ ℋ ) → ( 𝐴 ketbra 𝐵 ) = ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝐵 ) ·ℎ 𝐴 ) ) ) |
2 |
1
|
fveq1d |
⊢ ( ( 𝐴 ∈ ℋ ∧ 𝐵 ∈ ℋ ) → ( ( 𝐴 ketbra 𝐵 ) ‘ 𝐶 ) = ( ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝐵 ) ·ℎ 𝐴 ) ) ‘ 𝐶 ) ) |
3 |
|
oveq1 |
⊢ ( 𝑥 = 𝐶 → ( 𝑥 ·ih 𝐵 ) = ( 𝐶 ·ih 𝐵 ) ) |
4 |
3
|
oveq1d |
⊢ ( 𝑥 = 𝐶 → ( ( 𝑥 ·ih 𝐵 ) ·ℎ 𝐴 ) = ( ( 𝐶 ·ih 𝐵 ) ·ℎ 𝐴 ) ) |
5 |
|
eqid |
⊢ ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝐵 ) ·ℎ 𝐴 ) ) = ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝐵 ) ·ℎ 𝐴 ) ) |
6 |
|
ovex |
⊢ ( ( 𝐶 ·ih 𝐵 ) ·ℎ 𝐴 ) ∈ V |
7 |
4 5 6
|
fvmpt |
⊢ ( 𝐶 ∈ ℋ → ( ( 𝑥 ∈ ℋ ↦ ( ( 𝑥 ·ih 𝐵 ) ·ℎ 𝐴 ) ) ‘ 𝐶 ) = ( ( 𝐶 ·ih 𝐵 ) ·ℎ 𝐴 ) ) |
8 |
2 7
|
sylan9eq |
⊢ ( ( ( 𝐴 ∈ ℋ ∧ 𝐵 ∈ ℋ ) ∧ 𝐶 ∈ ℋ ) → ( ( 𝐴 ketbra 𝐵 ) ‘ 𝐶 ) = ( ( 𝐶 ·ih 𝐵 ) ·ℎ 𝐴 ) ) |
9 |
8
|
3impa |
⊢ ( ( 𝐴 ∈ ℋ ∧ 𝐵 ∈ ℋ ∧ 𝐶 ∈ ℋ ) → ( ( 𝐴 ketbra 𝐵 ) ‘ 𝐶 ) = ( ( 𝐶 ·ih 𝐵 ) ·ℎ 𝐴 ) ) |