| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simpl2l | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐵  ∈  On ) | 
						
							| 2 |  | eloni | ⊢ ( 𝐵  ∈  On  →  Ord  𝐵 ) | 
						
							| 3 | 1 2 | syl | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  Ord  𝐵 ) | 
						
							| 4 |  | simpl3l | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐷  ∈  On ) | 
						
							| 5 |  | eloni | ⊢ ( 𝐷  ∈  On  →  Ord  𝐷 ) | 
						
							| 6 | 4 5 | syl | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  Ord  𝐷 ) | 
						
							| 7 |  | ordtri3or | ⊢ ( ( Ord  𝐵  ∧  Ord  𝐷 )  →  ( 𝐵  ∈  𝐷  ∨  𝐵  =  𝐷  ∨  𝐷  ∈  𝐵 ) ) | 
						
							| 8 | 3 6 7 | syl2anc | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐵  ∈  𝐷  ∨  𝐵  =  𝐷  ∨  𝐷  ∈  𝐵 ) ) | 
						
							| 9 |  | simpr | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) | 
						
							| 10 |  | simpl1l | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐴  ∈  On ) | 
						
							| 11 |  | omcl | ⊢ ( ( 𝐴  ∈  On  ∧  𝐷  ∈  On )  →  ( 𝐴  ·o  𝐷 )  ∈  On ) | 
						
							| 12 | 10 4 11 | syl2anc | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐴  ·o  𝐷 )  ∈  On ) | 
						
							| 13 |  | simpl3r | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐸  ∈  𝐴 ) | 
						
							| 14 |  | onelon | ⊢ ( ( 𝐴  ∈  On  ∧  𝐸  ∈  𝐴 )  →  𝐸  ∈  On ) | 
						
							| 15 | 10 13 14 | syl2anc | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐸  ∈  On ) | 
						
							| 16 |  | oacl | ⊢ ( ( ( 𝐴  ·o  𝐷 )  ∈  On  ∧  𝐸  ∈  On )  →  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  On ) | 
						
							| 17 | 12 15 16 | syl2anc | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  On ) | 
						
							| 18 |  | eloni | ⊢ ( ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  On  →  Ord  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) | 
						
							| 19 |  | ordirr | ⊢ ( Ord  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  →  ¬  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) | 
						
							| 20 | 17 18 19 | 3syl | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ¬  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) | 
						
							| 21 | 9 20 | eqneltrd | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ¬  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  ∈  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) | 
						
							| 22 |  | orc | ⊢ ( 𝐵  ∈  𝐷  →  ( 𝐵  ∈  𝐷  ∨  ( 𝐵  =  𝐷  ∧  𝐶  ∈  𝐸 ) ) ) | 
						
							| 23 |  | omeulem2 | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  →  ( ( 𝐵  ∈  𝐷  ∨  ( 𝐵  =  𝐷  ∧  𝐶  ∈  𝐸 ) )  →  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  ∈  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) ) | 
						
							| 24 | 23 | adantr | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( ( 𝐵  ∈  𝐷  ∨  ( 𝐵  =  𝐷  ∧  𝐶  ∈  𝐸 ) )  →  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  ∈  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) ) | 
						
							| 25 | 22 24 | syl5 | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐵  ∈  𝐷  →  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  ∈  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) ) | 
						
							| 26 | 21 25 | mtod | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ¬  𝐵  ∈  𝐷 ) | 
						
							| 27 | 26 | pm2.21d | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐵  ∈  𝐷  →  𝐵  =  𝐷 ) ) | 
						
							| 28 |  | idd | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐵  =  𝐷  →  𝐵  =  𝐷 ) ) | 
						
							| 29 | 20 9 | neleqtrrd | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ¬  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 ) ) | 
						
							| 30 |  | orc | ⊢ ( 𝐷  ∈  𝐵  →  ( 𝐷  ∈  𝐵  ∨  ( 𝐷  =  𝐵  ∧  𝐸  ∈  𝐶 ) ) ) | 
						
							| 31 |  | simpl1r | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐴  ≠  ∅ ) | 
						
							| 32 |  | simpl2r | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐶  ∈  𝐴 ) | 
						
							| 33 |  | omeulem2 | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 ) )  →  ( ( 𝐷  ∈  𝐵  ∨  ( 𝐷  =  𝐵  ∧  𝐸  ∈  𝐶 ) )  →  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 ) ) ) | 
						
							| 34 | 10 31 4 13 1 32 33 | syl222anc | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( ( 𝐷  ∈  𝐵  ∨  ( 𝐷  =  𝐵  ∧  𝐸  ∈  𝐶 ) )  →  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 ) ) ) | 
						
							| 35 | 30 34 | syl5 | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐷  ∈  𝐵  →  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 ) ) ) | 
						
							| 36 | 29 35 | mtod | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ¬  𝐷  ∈  𝐵 ) | 
						
							| 37 | 36 | pm2.21d | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐷  ∈  𝐵  →  𝐵  =  𝐷 ) ) | 
						
							| 38 | 27 28 37 | 3jaod | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( ( 𝐵  ∈  𝐷  ∨  𝐵  =  𝐷  ∨  𝐷  ∈  𝐵 )  →  𝐵  =  𝐷 ) ) | 
						
							| 39 | 8 38 | mpd | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐵  =  𝐷 ) | 
						
							| 40 |  | onelon | ⊢ ( ( 𝐴  ∈  On  ∧  𝐶  ∈  𝐴 )  →  𝐶  ∈  On ) | 
						
							| 41 |  | eloni | ⊢ ( 𝐶  ∈  On  →  Ord  𝐶 ) | 
						
							| 42 | 40 41 | syl | ⊢ ( ( 𝐴  ∈  On  ∧  𝐶  ∈  𝐴 )  →  Ord  𝐶 ) | 
						
							| 43 | 10 32 42 | syl2anc | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  Ord  𝐶 ) | 
						
							| 44 |  | eloni | ⊢ ( 𝐸  ∈  On  →  Ord  𝐸 ) | 
						
							| 45 | 14 44 | syl | ⊢ ( ( 𝐴  ∈  On  ∧  𝐸  ∈  𝐴 )  →  Ord  𝐸 ) | 
						
							| 46 | 10 13 45 | syl2anc | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  Ord  𝐸 ) | 
						
							| 47 |  | ordtri3or | ⊢ ( ( Ord  𝐶  ∧  Ord  𝐸 )  →  ( 𝐶  ∈  𝐸  ∨  𝐶  =  𝐸  ∨  𝐸  ∈  𝐶 ) ) | 
						
							| 48 | 43 46 47 | syl2anc | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐶  ∈  𝐸  ∨  𝐶  =  𝐸  ∨  𝐸  ∈  𝐶 ) ) | 
						
							| 49 |  | olc | ⊢ ( ( 𝐵  =  𝐷  ∧  𝐶  ∈  𝐸 )  →  ( 𝐵  ∈  𝐷  ∨  ( 𝐵  =  𝐷  ∧  𝐶  ∈  𝐸 ) ) ) | 
						
							| 50 | 49 24 | syl5 | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( ( 𝐵  =  𝐷  ∧  𝐶  ∈  𝐸 )  →  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  ∈  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) ) | 
						
							| 51 | 39 50 | mpand | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐶  ∈  𝐸  →  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  ∈  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) ) | 
						
							| 52 | 21 51 | mtod | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ¬  𝐶  ∈  𝐸 ) | 
						
							| 53 | 52 | pm2.21d | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐶  ∈  𝐸  →  𝐶  =  𝐸 ) ) | 
						
							| 54 |  | idd | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐶  =  𝐸  →  𝐶  =  𝐸 ) ) | 
						
							| 55 | 39 | eqcomd | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐷  =  𝐵 ) | 
						
							| 56 |  | olc | ⊢ ( ( 𝐷  =  𝐵  ∧  𝐸  ∈  𝐶 )  →  ( 𝐷  ∈  𝐵  ∨  ( 𝐷  =  𝐵  ∧  𝐸  ∈  𝐶 ) ) ) | 
						
							| 57 | 56 34 | syl5 | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( ( 𝐷  =  𝐵  ∧  𝐸  ∈  𝐶 )  →  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 ) ) ) | 
						
							| 58 | 55 57 | mpand | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐸  ∈  𝐶  →  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ∈  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 ) ) ) | 
						
							| 59 | 29 58 | mtod | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ¬  𝐸  ∈  𝐶 ) | 
						
							| 60 | 59 | pm2.21d | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐸  ∈  𝐶  →  𝐶  =  𝐸 ) ) | 
						
							| 61 | 53 54 60 | 3jaod | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( ( 𝐶  ∈  𝐸  ∨  𝐶  =  𝐸  ∨  𝐸  ∈  𝐶 )  →  𝐶  =  𝐸 ) ) | 
						
							| 62 | 48 61 | mpd | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  𝐶  =  𝐸 ) | 
						
							| 63 | 39 62 | jca | ⊢ ( ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  ∧  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) )  →  ( 𝐵  =  𝐷  ∧  𝐶  =  𝐸 ) ) | 
						
							| 64 | 63 | ex | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  →  ( ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  →  ( 𝐵  =  𝐷  ∧  𝐶  =  𝐸 ) ) ) | 
						
							| 65 |  | oveq2 | ⊢ ( 𝐵  =  𝐷  →  ( 𝐴  ·o  𝐵 )  =  ( 𝐴  ·o  𝐷 ) ) | 
						
							| 66 |  | id | ⊢ ( 𝐶  =  𝐸  →  𝐶  =  𝐸 ) | 
						
							| 67 | 65 66 | oveqan12d | ⊢ ( ( 𝐵  =  𝐷  ∧  𝐶  =  𝐸 )  →  ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 ) ) | 
						
							| 68 | 64 67 | impbid1 | ⊢ ( ( ( 𝐴  ∈  On  ∧  𝐴  ≠  ∅ )  ∧  ( 𝐵  ∈  On  ∧  𝐶  ∈  𝐴 )  ∧  ( 𝐷  ∈  On  ∧  𝐸  ∈  𝐴 ) )  →  ( ( ( 𝐴  ·o  𝐵 )  +o  𝐶 )  =  ( ( 𝐴  ·o  𝐷 )  +o  𝐸 )  ↔  ( 𝐵  =  𝐷  ∧  𝐶  =  𝐸 ) ) ) |