Metamath Proof Explorer


Theorem strlem3

Description: Lemma for strong state theorem: the function S , that maps a closed subspace to the square of the norm of its projection onto a unit vector, is a state. This lemma restates the hypotheses in a more convenient form to work with. (Contributed by NM, 28-Oct-1999) (New usage is discouraged.)

Ref Expression
Hypotheses strlem3.1 ⊢ 𝑆 = ( 𝑥 ∈ Cℋ ↦ ( ( normℎ ‘ ( ( projℎ ‘ 𝑥 ) ‘ 𝑢 ) ) ↑ 2 ) )
strlem3.2 ⊢ ( 𝜑 ↔ ( 𝑢 ∈ ( 𝐴 ∖ 𝐵 ) ∧ ( normℎ ‘ 𝑢 ) = 1 ) )
strlem3.3 ⊢ 𝐴 ∈ Cℋ
strlem3.4 ⊢ 𝐵 ∈ Cℋ
Assertion strlem3 ( 𝜑 → 𝑆 ∈ States )

Proof

Step Hyp Ref Expression
1 strlem3.1 ⊢ 𝑆 = ( 𝑥 ∈ Cℋ ↦ ( ( normℎ ‘ ( ( projℎ ‘ 𝑥 ) ‘ 𝑢 ) ) ↑ 2 ) )
2 strlem3.2 ⊢ ( 𝜑 ↔ ( 𝑢 ∈ ( 𝐴 ∖ 𝐵 ) ∧ ( normℎ ‘ 𝑢 ) = 1 ) )
3 strlem3.3 ⊢ 𝐴 ∈ Cℋ
4 strlem3.4 ⊢ 𝐵 ∈ Cℋ
5 eldifi ⊢ ( 𝑢 ∈ ( 𝐴 ∖ 𝐵 ) → 𝑢 ∈ 𝐴 )
6 3 cheli ⊢ ( 𝑢 ∈ 𝐴 → 𝑢 ∈ ℋ )
7 5 6 syl ⊢ ( 𝑢 ∈ ( 𝐴 ∖ 𝐵 ) → 𝑢 ∈ ℋ )
8 1 strlem3a ⊢ ( ( 𝑢 ∈ ℋ ∧ ( normℎ ‘ 𝑢 ) = 1 ) → 𝑆 ∈ States )
9 7 8 sylan ⊢ ( ( 𝑢 ∈ ( 𝐴 ∖ 𝐵 ) ∧ ( normℎ ‘ 𝑢 ) = 1 ) → 𝑆 ∈ States )
10 2 9 sylbi ⊢ ( 𝜑 → 𝑆 ∈ States )