Metamath Proof Explorer


Axiom ax-his3

Description: Associative law for inner product. Postulate (S3) of Beran p. 95. Warning: Mathematics textbooks usually use our version of the axiom. Physics textbooks, on the other hand, usually replace the left-hand side with ( B .ih ( A .h C ) ) (e.g., Equation 1.21b of Hughes p. 44; Definition (iii) of ReedSimon p. 36). See the comments in df-bra for why the physics definition is swapped. (Contributed by NM, 29-May-1999) (New usage is discouraged.)

Ref Expression
Assertion ax-his3 A B C A B ih C = A B ih C

Detailed syntax breakdown

Step Hyp Ref Expression
0 cA class A
1 cc class
2 0 1 wcel wff A
3 cB class B
4 chba class
5 3 4 wcel wff B
6 cC class C
7 6 4 wcel wff C
8 2 5 7 w3a wff A B C
9 csm class
10 0 3 9 co class A B
11 csp class ih
12 10 6 11 co class A B ih C
13 cmul class ×
14 3 6 11 co class B ih C
15 0 14 13 co class A B ih C
16 12 15 wceq wff A B ih C = A B ih C
17 8 16 wi wff A B C A B ih C = A B ih C