| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eqid | ⊢ ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) }  =  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } | 
						
							| 2 | 1 | oeeulem | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) }  ∈  On  ∧  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ⊆  𝐵  ∧  𝐵  ∈  ( 𝐴  ↑o  suc  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ) ) | 
						
							| 3 | 2 | simp1d | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) }  ∈  On ) | 
						
							| 4 |  | fvexd | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( 1st  ‘ ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) ) )  ∈  V ) | 
						
							| 5 |  | fvexd | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( 2nd  ‘ ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) ) )  ∈  V ) | 
						
							| 6 |  | eqid | ⊢ ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) )  =  ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) ) | 
						
							| 7 |  | eqid | ⊢ ( 1st  ‘ ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) ) )  =  ( 1st  ‘ ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) ) ) | 
						
							| 8 |  | eqid | ⊢ ( 2nd  ‘ ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) ) )  =  ( 2nd  ‘ ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) ) ) | 
						
							| 9 | 1 6 7 8 | oeeui | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 )  ↔  ( 𝑥  =  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) }  ∧  𝑦  =  ( 1st  ‘ ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) ) )  ∧  𝑧  =  ( 2nd  ‘ ( ℩ 𝑑 ∃ 𝑏  ∈  On ∃ 𝑐  ∈  ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } ) ( 𝑑  =  〈 𝑏 ,  𝑐 〉  ∧  ( ( ( 𝐴  ↑o  ∪  ∩  { 𝑎  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑎 ) } )  ·o  𝑏 )  +o  𝑐 )  =  𝐵 ) ) ) ) ) ) | 
						
							| 10 | 3 4 5 9 | euotd | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ∃! 𝑤 ∃ 𝑥 ∃ 𝑦 ∃ 𝑧 ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) | 
						
							| 11 |  | df-3an | ⊢ ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ↔  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ) ) | 
						
							| 12 | 11 | biancomi | ⊢ ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ↔  ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) ) ) ) | 
						
							| 13 | 12 | anbi1i | ⊢ ( ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 )  ↔  ( ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) | 
						
							| 14 | 13 | anbi2i | ⊢ ( ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) | 
						
							| 15 |  | an12 | ⊢ ( ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ( ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) ) )  ∧  ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) | 
						
							| 16 |  | anass | ⊢ ( ( ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) ) )  ∧  ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) ) | 
						
							| 17 | 14 15 16 | 3bitri | ⊢ ( ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) ) | 
						
							| 18 | 17 | exbii | ⊢ ( ∃ 𝑧 ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ∃ 𝑧 ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) ) | 
						
							| 19 |  | df-rex | ⊢ ( ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ∃ 𝑧 ( 𝑧  ∈  ( 𝐴  ↑o  𝑥 )  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) ) | 
						
							| 20 |  | r19.42v | ⊢ ( ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) | 
						
							| 21 | 18 19 20 | 3bitr2i | ⊢ ( ∃ 𝑧 ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) | 
						
							| 22 | 21 | 2exbii | ⊢ ( ∃ 𝑥 ∃ 𝑦 ∃ 𝑧 ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ∃ 𝑥 ∃ 𝑦 ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) | 
						
							| 23 |  | r2ex | ⊢ ( ∃ 𝑥  ∈  On ∃ 𝑦  ∈  ( 𝐴  ∖  1o ) ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 )  ↔  ∃ 𝑥 ∃ 𝑦 ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o ) )  ∧  ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) ) | 
						
							| 24 | 22 23 | bitr4i | ⊢ ( ∃ 𝑥 ∃ 𝑦 ∃ 𝑧 ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ∃ 𝑥  ∈  On ∃ 𝑦  ∈  ( 𝐴  ∖  1o ) ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) | 
						
							| 25 | 24 | eubii | ⊢ ( ∃! 𝑤 ∃ 𝑥 ∃ 𝑦 ∃ 𝑧 ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( 𝑥  ∈  On  ∧  𝑦  ∈  ( 𝐴  ∖  1o )  ∧  𝑧  ∈  ( 𝐴  ↑o  𝑥 ) )  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) )  ↔  ∃! 𝑤 ∃ 𝑥  ∈  On ∃ 𝑦  ∈  ( 𝐴  ∖  1o ) ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) | 
						
							| 26 | 10 25 | sylib | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ∃! 𝑤 ∃ 𝑥  ∈  On ∃ 𝑦  ∈  ( 𝐴  ∖  1o ) ∃ 𝑧  ∈  ( 𝐴  ↑o  𝑥 ) ( 𝑤  =  〈 𝑥 ,  𝑦 ,  𝑧 〉  ∧  ( ( ( 𝐴  ↑o  𝑥 )  ·o  𝑦 )  +o  𝑧 )  =  𝐵 ) ) |