Description: Vector addition is associative. (Contributed by NM, 3-Sep-1999) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ax-hvass | ⊢ ( ( 𝐴 ∈ ℋ ∧ 𝐵 ∈ ℋ ∧ 𝐶 ∈ 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 ∈ ℋ | 
| 3 | cB | ⊢ 𝐵 | |
| 4 | 3 1 | wcel | ⊢ 𝐵 ∈ ℋ | 
| 5 | cC | ⊢ 𝐶 | |
| 6 | 5 1 | wcel | ⊢ 𝐶 ∈ ℋ | 
| 7 | 2 4 6 | w3a | ⊢ ( 𝐴 ∈ ℋ ∧ 𝐵 ∈ ℋ ∧ 𝐶 ∈ 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 ∈ ℋ ∧ 𝐵 ∈ ℋ ∧ 𝐶 ∈ ℋ ) → ( ( 𝐴 +ℎ 𝐵 ) +ℎ 𝐶 ) = ( 𝐴 +ℎ ( 𝐵 +ℎ 𝐶 ) ) ) |