Metamath Proof Explorer


Theorem strlem4

Description: Lemma for strong state theorem. (Contributed by NM, 2-Nov-1999) (New usage is discouraged.)

Ref Expression
Hypotheses strlem3.1 ⊢ S = x ∈ C ℋ ⟼ norm ℎ ⁡ proj ℎ ⁡ x ⁡ u 2
strlem3.2 ⊢ φ ↔ u ∈ A ∖ B ∧ norm ℎ ⁡ u = 1
strlem3.3 ⊢ A ∈ C ℋ
strlem3.4 ⊢ B ∈ C ℋ
Assertion strlem4 ⊢ φ → S ⁡ A = 1

Proof

Step Hyp Ref Expression
1 strlem3.1 ⊢ S = x ∈ C ℋ ⟼ norm ℎ ⁡ proj ℎ ⁡ x ⁡ u 2
2 strlem3.2 ⊢ φ ↔ u ∈ A ∖ B ∧ norm ℎ ⁡ u = 1
3 strlem3.3 ⊢ A ∈ C ℋ
4 strlem3.4 ⊢ B ∈ C ℋ
5 1 strlem2 ⊢ A ∈ C ℋ → S ⁡ A = norm ℎ ⁡ proj ℎ ⁡ A ⁡ u 2
6 3 5 ax-mp ⊢ S ⁡ A = norm ℎ ⁡ proj ℎ ⁡ A ⁡ u 2
7 eldifi ⊢ u ∈ A ∖ B → u ∈ A
8 pjid ⊢ A ∈ C ℋ ∧ u ∈ A → proj ℎ ⁡ A ⁡ u = u
9 3 8 mpan ⊢ u ∈ A → proj ℎ ⁡ A ⁡ u = u
10 9 fveq2d ⊢ u ∈ A → norm ℎ ⁡ proj ℎ ⁡ A ⁡ u = norm ℎ ⁡ u
11 eqeq2 ⊢ norm ℎ ⁡ u = 1 → norm ℎ ⁡ proj ℎ ⁡ A ⁡ u = norm ℎ ⁡ u ↔ norm ℎ ⁡ proj ℎ ⁡ A ⁡ u = 1
12 10 11 imbitrid ⊢ norm ℎ ⁡ u = 1 → u ∈ A → norm ℎ ⁡ proj ℎ ⁡ A ⁡ u = 1
13 7 12 mpan9 ⊢ u ∈ A ∖ B ∧ norm ℎ ⁡ u = 1 → norm ℎ ⁡ proj ℎ ⁡ A ⁡ u = 1
14 2 13 sylbi ⊢ φ → norm ℎ ⁡ proj ℎ ⁡ A ⁡ u = 1
15 14 oveq1d ⊢ φ → norm ℎ ⁡ proj ℎ ⁡ A ⁡ u 2 = 1 2
16 sq1 ⊢ 1 2 = 1
17 15 16 eqtrdi ⊢ φ → norm ℎ ⁡ proj ℎ ⁡ A ⁡ u 2 = 1
18 6 17 eqtrid ⊢ φ → S ⁡ A = 1