Description: Vector addition is associative. (Contributed by NM, 3-Sep-1999) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ax-hvass | |- ( ( A e. ~H /\ B e. ~H /\ C e. ~H ) -> ( ( A +h B ) +h C ) = ( A +h ( B +h C ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cA | |- A |
|
| 1 | chba | |- ~H |
|
| 2 | 0 1 | wcel | |- A e. ~H |
| 3 | cB | |- B |
|
| 4 | 3 1 | wcel | |- B e. ~H |
| 5 | cC | |- C |
|
| 6 | 5 1 | wcel | |- C e. ~H |
| 7 | 2 4 6 | w3a | |- ( A e. ~H /\ B e. ~H /\ C e. ~H ) |
| 8 | cva | |- +h |
|
| 9 | 0 3 8 | co | |- ( A +h B ) |
| 10 | 9 5 8 | co | |- ( ( A +h B ) +h C ) |
| 11 | 3 5 8 | co | |- ( B +h C ) |
| 12 | 0 11 8 | co | |- ( A +h ( B +h C ) ) |
| 13 | 10 12 | wceq | |- ( ( A +h B ) +h C ) = ( A +h ( B +h C ) ) |
| 14 | 7 13 | wi | |- ( ( A e. ~H /\ B e. ~H /\ C e. ~H ) -> ( ( A +h B ) +h C ) = ( A +h ( B +h C ) ) ) |