Description: Define the ordinal multiplication operation. (Contributed by NM, 26-Aug-1995)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-omul | ⊢ ·o = ( 𝑥 ∈ On , 𝑦 ∈ On ↦ ( rec ( ( 𝑧 ∈ V ↦ ( 𝑧 +o 𝑥 ) ) , ∅ ) ‘ 𝑦 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | comu | ⊢ ·o | |
| 1 | vx | ⊢ 𝑥 | |
| 2 | con0 | ⊢ On | |
| 3 | vy | ⊢ 𝑦 | |
| 4 | vz | ⊢ 𝑧 | |
| 5 | cvv | ⊢ V | |
| 6 | 4 | cv | ⊢ 𝑧 |
| 7 | coa | ⊢ +o | |
| 8 | 1 | cv | ⊢ 𝑥 |
| 9 | 6 8 7 | co | ⊢ ( 𝑧 +o 𝑥 ) |
| 10 | 4 5 9 | cmpt | ⊢ ( 𝑧 ∈ V ↦ ( 𝑧 +o 𝑥 ) ) |
| 11 | c0 | ⊢ ∅ | |
| 12 | 10 11 | crdg | ⊢ rec ( ( 𝑧 ∈ V ↦ ( 𝑧 +o 𝑥 ) ) , ∅ ) |
| 13 | 3 | cv | ⊢ 𝑦 |
| 14 | 13 12 | cfv | ⊢ ( rec ( ( 𝑧 ∈ V ↦ ( 𝑧 +o 𝑥 ) ) , ∅ ) ‘ 𝑦 ) |
| 15 | 1 3 2 2 14 | cmpo | ⊢ ( 𝑥 ∈ On , 𝑦 ∈ On ↦ ( rec ( ( 𝑧 ∈ V ↦ ( 𝑧 +o 𝑥 ) ) , ∅ ) ‘ 𝑦 ) ) |
| 16 | 0 15 | wceq | ⊢ ·o = ( 𝑥 ∈ On , 𝑦 ∈ On ↦ ( rec ( ( 𝑧 ∈ V ↦ ( 𝑧 +o 𝑥 ) ) , ∅ ) ‘ 𝑦 ) ) |