Metamath Proof Explorer


Theorem hstpyth

Description: Pythagorean property of a Hilbert-space-valued state for orthogonal vectors A and B . (Contributed by NM, 26-Jun-2006) (New usage is discouraged.)

Ref Expression
Assertion hstpyth S CHStates A C B C A B norm S A B 2 = norm S A 2 + norm S B 2

Proof

Step Hyp Ref Expression
1 hstosum S CHStates A C B C A B S A B = S A + S B
2 1 fveq2d S CHStates A C B C A B norm S A B = norm S A + S B
3 2 oveq1d S CHStates A C B C A B norm S A B 2 = norm S A + S B 2
4 hstcl S CHStates A C S A
5 4 adantr S CHStates A C B C A B S A
6 hstcl S CHStates B C S B
7 6 ad2ant2r S CHStates A C B C A B S B
8 hstorth S CHStates A C B C A B S A ih S B = 0
9 normpyth S A S B S A ih S B = 0 norm S A + S B 2 = norm S A 2 + norm S B 2
10 9 3impia S A S B S A ih S B = 0 norm S A + S B 2 = norm S A 2 + norm S B 2
11 5 7 8 10 syl3anc S CHStates A C B C A B norm S A + S B 2 = norm S A 2 + norm S B 2
12 3 11 eqtrd S CHStates A C B C A B norm S A B 2 = norm S A 2 + norm S B 2