Detailed syntax breakdown of Axiom ax-hvass
| Step | Hyp | Ref
| Expression |
| 1 | | cA |
. . . 4
class A |
| 2 | | chil 8727 |
. . . 4
class ℋ |
| 3 | 1, 2 | wcel 955 |
. . 3
wff A ∈
ℋ |
| 4 | | cB |
. . . 4
class B |
| 5 | 4, 2 | wcel 955 |
. . 3
wff B ∈
ℋ |
| 6 | | cC |
. . . 4
class C |
| 7 | 6, 2 | wcel 955 |
. . 3
wff C ∈
ℋ |
| 8 | 3, 5, 7 | w3a 773 |
. 2
wff (A ∈
ℋ ⋀ B ∈ ℋ ⋀
C ∈ ℋ ) |
| 9 | | cva 8728 |
. . . . 5
class +h |
| 10 | 1, 4, 9 | co 3948 |
. . . 4
class (A
+h B) |
| 11 | 10, 6, 9 | co 3948 |
. . 3
class ((A
+h B)
+h C) |
| 12 | 4, 6, 9 | co 3948 |
. . . 4
class (B
+h C) |
| 13 | 1, 12, 9 | co 3948 |
. . 3
class (A
+h (B
+h C)) |
| 14 | 11, 13 | wceq 953 |
. 2
wff ((A
+h B)
+h C) = (A +h (B +h C)) |
| 15 | 8, 14 | wi 3 |
1
wff ((A ∈
ℋ ⋀ B ∈ ℋ ⋀
C ∈ ℋ ) → ((A +h B) +h C) = (A
+h (B
+h C))) |