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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 e. CC /\ B e. ~H /\ C e. ~H ) -> ( ( A .h B ) .ih C ) = ( A x. ( B .ih C ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cA | |- A |
|
| 1 | cc | |- CC |
|
| 2 | 0 1 | wcel | |- A e. CC |
| 3 | cB | |- B |
|
| 4 | chba | |- ~H |
|
| 5 | 3 4 | wcel | |- B e. ~H |
| 6 | cC | |- C |
|
| 7 | 6 4 | wcel | |- C e. ~H |
| 8 | 2 5 7 | w3a | |- ( A e. CC /\ B e. ~H /\ C e. ~H ) |
| 9 | csm | |- .h |
|
| 10 | 0 3 9 | co | |- ( A .h B ) |
| 11 | csp | |- .ih |
|
| 12 | 10 6 11 | co | |- ( ( A .h B ) .ih C ) |
| 13 | cmul | |- x. |
|
| 14 | 3 6 11 | co | |- ( B .ih C ) |
| 15 | 0 14 13 | co | |- ( A x. ( B .ih C ) ) |
| 16 | 12 15 | wceq | |- ( ( A .h B ) .ih C ) = ( A x. ( B .ih C ) ) |
| 17 | 8 16 | wi | |- ( ( A e. CC /\ B e. ~H /\ C e. ~H ) -> ( ( A .h B ) .ih C ) = ( A x. ( B .ih C ) ) ) |