| Step | Hyp | Ref | Expression | 
						
							| 1 |  | omeulem1 | ⊢ ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  →  ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) | 
						
							| 2 |  | opex | ⊢ 〈 𝑥 ,  𝑦 〉  ∈  V | 
						
							| 3 | 2 | isseti | ⊢ ∃ 𝑧 𝑧  =  〈 𝑥 ,  𝑦 〉 | 
						
							| 4 |  | 19.41v | ⊢ ( ∃ 𝑧 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ↔  ( ∃ 𝑧 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) ) | 
						
							| 5 | 3 4 | mpbiran | ⊢ ( ∃ 𝑧 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ↔  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) | 
						
							| 6 | 5 | rexbii | ⊢ ( ∃ 𝑦  ∈  𝐴 ∃ 𝑧 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ↔  ∃ 𝑦  ∈  𝐴 ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) | 
						
							| 7 |  | rexcom4 | ⊢ ( ∃ 𝑦  ∈  𝐴 ∃ 𝑧 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ↔  ∃ 𝑧 ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) ) | 
						
							| 8 | 6 7 | bitr3i | ⊢ ( ∃ 𝑦  ∈  𝐴 ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵  ↔  ∃ 𝑧 ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) ) | 
						
							| 9 | 8 | rexbii | ⊢ ( ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵  ↔  ∃ 𝑥  ∈  On ∃ 𝑧 ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) ) | 
						
							| 10 |  | rexcom4 | ⊢ ( ∃ 𝑥  ∈  On ∃ 𝑧 ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ↔  ∃ 𝑧 ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) ) | 
						
							| 11 | 9 10 | bitri | ⊢ ( ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵  ↔  ∃ 𝑧 ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) ) | 
						
							| 12 | 1 11 | sylib | ⊢ ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  →  ∃ 𝑧 ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) ) | 
						
							| 13 |  | simp2rl | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝑧  =  〈 𝑥 ,  𝑦 〉 ) | 
						
							| 14 |  | simp3rl | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝑡  =  〈 𝑟 ,  𝑠 〉 ) | 
						
							| 15 |  | simp2rr | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) | 
						
							| 16 |  | simp3rr | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) | 
						
							| 17 | 15 16 | eqtr4d | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 ) ) | 
						
							| 18 |  | simp11 | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝐴  ∈  On ) | 
						
							| 19 |  | simp13 | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝐴  ≠  ∅ ) | 
						
							| 20 |  | simp2ll | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝑥  ∈  On ) | 
						
							| 21 |  | simp2lr | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝑦  ∈  𝐴 ) | 
						
							| 22 |  | simp3ll | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝑟  ∈  On ) | 
						
							| 23 |  | simp3lr | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝑠  ∈  𝐴 ) | 
						
							| 24 |  | omopth2 | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 ) )  →  ( ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  ↔  ( 𝑥  =  𝑟  ∧  𝑦  =  𝑠 ) ) ) | 
						
							| 25 | 18 19 20 21 22 23 24 | syl222anc | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  ( ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  ↔  ( 𝑥  =  𝑟  ∧  𝑦  =  𝑠 ) ) ) | 
						
							| 26 | 17 25 | mpbid | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  ( 𝑥  =  𝑟  ∧  𝑦  =  𝑠 ) ) | 
						
							| 27 |  | opeq12 | ⊢ ( ( 𝑥  =  𝑟  ∧  𝑦  =  𝑠 )  →  〈 𝑥 ,  𝑦 〉  =  〈 𝑟 ,  𝑠 〉 ) | 
						
							| 28 | 26 27 | syl | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  〈 𝑥 ,  𝑦 〉  =  〈 𝑟 ,  𝑠 〉 ) | 
						
							| 29 | 14 28 | eqtr4d | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝑡  =  〈 𝑥 ,  𝑦 〉 ) | 
						
							| 30 | 13 29 | eqtr4d | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  ∧  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) )  →  𝑧  =  𝑡 ) | 
						
							| 31 | 30 | 3expia | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) ) )  →  ( ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) )  →  𝑧  =  𝑡 ) ) | 
						
							| 32 | 31 | exp4b | ⊢ ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  →  ( ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  ∧  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  →  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  →  ( ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 )  →  𝑧  =  𝑡 ) ) ) ) | 
						
							| 33 | 32 | expd | ⊢ ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  →  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  𝐴 )  →  ( ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  →  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  →  ( ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 )  →  𝑧  =  𝑡 ) ) ) ) ) | 
						
							| 34 | 33 | rexlimdvv | ⊢ ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  →  ( ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  →  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  →  ( ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 )  →  𝑧  =  𝑡 ) ) ) ) | 
						
							| 35 | 34 | imp | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  →  ( ( 𝑟  ∈  On  ∧  𝑠  ∈  𝐴 )  →  ( ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 )  →  𝑧  =  𝑡 ) ) ) | 
						
							| 36 | 35 | rexlimdvv | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) )  →  ( ∃ 𝑟  ∈  On ∃ 𝑠  ∈  𝐴 ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 )  →  𝑧  =  𝑡 ) ) | 
						
							| 37 | 36 | expimpd | ⊢ ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  →  ( ( ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ∧  ∃ 𝑟  ∈  On ∃ 𝑠  ∈  𝐴 ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) )  →  𝑧  =  𝑡 ) ) | 
						
							| 38 | 37 | alrimivv | ⊢ ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  →  ∀ 𝑧 ∀ 𝑡 ( ( ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ∧  ∃ 𝑟  ∈  On ∃ 𝑠  ∈  𝐴 ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) )  →  𝑧  =  𝑡 ) ) | 
						
							| 39 |  | opeq1 | ⊢ ( 𝑥  =  𝑟  →  〈 𝑥 ,  𝑦 〉  =  〈 𝑟 ,  𝑦 〉 ) | 
						
							| 40 | 39 | eqeq2d | ⊢ ( 𝑥  =  𝑟  →  ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ↔  𝑧  =  〈 𝑟 ,  𝑦 〉 ) ) | 
						
							| 41 |  | oveq2 | ⊢ ( 𝑥  =  𝑟  →  ( 𝐴  ·o  𝑥 )  =  ( 𝐴  ·o  𝑟 ) ) | 
						
							| 42 | 41 | oveq1d | ⊢ ( 𝑥  =  𝑟  →  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  ( ( 𝐴  ·o  𝑟 )  +o  𝑦 ) ) | 
						
							| 43 | 42 | eqeq1d | ⊢ ( 𝑥  =  𝑟  →  ( ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵  ↔  ( ( 𝐴  ·o  𝑟 )  +o  𝑦 )  =  𝐵 ) ) | 
						
							| 44 | 40 43 | anbi12d | ⊢ ( 𝑥  =  𝑟  →  ( ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ↔  ( 𝑧  =  〈 𝑟 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑦 )  =  𝐵 ) ) ) | 
						
							| 45 |  | opeq2 | ⊢ ( 𝑦  =  𝑠  →  〈 𝑟 ,  𝑦 〉  =  〈 𝑟 ,  𝑠 〉 ) | 
						
							| 46 | 45 | eqeq2d | ⊢ ( 𝑦  =  𝑠  →  ( 𝑧  =  〈 𝑟 ,  𝑦 〉  ↔  𝑧  =  〈 𝑟 ,  𝑠 〉 ) ) | 
						
							| 47 |  | oveq2 | ⊢ ( 𝑦  =  𝑠  →  ( ( 𝐴  ·o  𝑟 )  +o  𝑦 )  =  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 ) ) | 
						
							| 48 | 47 | eqeq1d | ⊢ ( 𝑦  =  𝑠  →  ( ( ( 𝐴  ·o  𝑟 )  +o  𝑦 )  =  𝐵  ↔  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) | 
						
							| 49 | 46 48 | anbi12d | ⊢ ( 𝑦  =  𝑠  →  ( ( 𝑧  =  〈 𝑟 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑦 )  =  𝐵 )  ↔  ( 𝑧  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) ) | 
						
							| 50 | 44 49 | cbvrex2vw | ⊢ ( ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ↔  ∃ 𝑟  ∈  On ∃ 𝑠  ∈  𝐴 ( 𝑧  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) | 
						
							| 51 |  | eqeq1 | ⊢ ( 𝑧  =  𝑡  →  ( 𝑧  =  〈 𝑟 ,  𝑠 〉  ↔  𝑡  =  〈 𝑟 ,  𝑠 〉 ) ) | 
						
							| 52 | 51 | anbi1d | ⊢ ( 𝑧  =  𝑡  →  ( ( 𝑧  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 )  ↔  ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) ) | 
						
							| 53 | 52 | 2rexbidv | ⊢ ( 𝑧  =  𝑡  →  ( ∃ 𝑟  ∈  On ∃ 𝑠  ∈  𝐴 ( 𝑧  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 )  ↔  ∃ 𝑟  ∈  On ∃ 𝑠  ∈  𝐴 ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) ) | 
						
							| 54 | 50 53 | bitrid | ⊢ ( 𝑧  =  𝑡  →  ( ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ↔  ∃ 𝑟  ∈  On ∃ 𝑠  ∈  𝐴 ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) ) ) | 
						
							| 55 | 54 | eu4 | ⊢ ( ∃! 𝑧 ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ↔  ( ∃ 𝑧 ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ∧  ∀ 𝑧 ∀ 𝑡 ( ( ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 )  ∧  ∃ 𝑟  ∈  On ∃ 𝑠  ∈  𝐴 ( 𝑡  =  〈 𝑟 ,  𝑠 〉  ∧  ( ( 𝐴  ·o  𝑟 )  +o  𝑠 )  =  𝐵 ) )  →  𝑧  =  𝑡 ) ) ) | 
						
							| 56 | 12 38 55 | sylanbrc | ⊢ ( ( 𝐴  ∈  On  ∧  𝐵  ∈  On  ∧  𝐴  ≠  ∅ )  →  ∃! 𝑧 ∃ 𝑥  ∈  On ∃ 𝑦  ∈  𝐴 ( 𝑧  =  〈 𝑥 ,  𝑦 〉  ∧  ( ( 𝐴  ·o  𝑥 )  +o  𝑦 )  =  𝐵 ) ) |