| Step | Hyp | Ref | Expression | 
						
							| 1 |  | oeeu.1 | ⊢ 𝑋  =  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } | 
						
							| 2 |  | eldifi | ⊢ ( 𝐵  ∈  ( On  ∖  1o )  →  𝐵  ∈  On ) | 
						
							| 3 | 2 | adantl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝐵  ∈  On ) | 
						
							| 4 |  | onsuc | ⊢ ( 𝐵  ∈  On  →  suc  𝐵  ∈  On ) | 
						
							| 5 | 3 4 | syl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  suc  𝐵  ∈  On ) | 
						
							| 6 |  | oeworde | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  suc  𝐵  ∈  On )  →  suc  𝐵  ⊆  ( 𝐴  ↑o  suc  𝐵 ) ) | 
						
							| 7 | 5 6 | syldan | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  suc  𝐵  ⊆  ( 𝐴  ↑o  suc  𝐵 ) ) | 
						
							| 8 |  | sucidg | ⊢ ( 𝐵  ∈  On  →  𝐵  ∈  suc  𝐵 ) | 
						
							| 9 | 3 8 | syl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝐵  ∈  suc  𝐵 ) | 
						
							| 10 | 7 9 | sseldd | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝐵  ∈  ( 𝐴  ↑o  suc  𝐵 ) ) | 
						
							| 11 |  | oveq2 | ⊢ ( 𝑥  =  suc  𝐵  →  ( 𝐴  ↑o  𝑥 )  =  ( 𝐴  ↑o  suc  𝐵 ) ) | 
						
							| 12 | 11 | eleq2d | ⊢ ( 𝑥  =  suc  𝐵  →  ( 𝐵  ∈  ( 𝐴  ↑o  𝑥 )  ↔  𝐵  ∈  ( 𝐴  ↑o  suc  𝐵 ) ) ) | 
						
							| 13 | 12 | rspcev | ⊢ ( ( suc  𝐵  ∈  On  ∧  𝐵  ∈  ( 𝐴  ↑o  suc  𝐵 ) )  →  ∃ 𝑥  ∈  On 𝐵  ∈  ( 𝐴  ↑o  𝑥 ) ) | 
						
							| 14 | 5 10 13 | syl2anc | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ∃ 𝑥  ∈  On 𝐵  ∈  ( 𝐴  ↑o  𝑥 ) ) | 
						
							| 15 |  | onintrab2 | ⊢ ( ∃ 𝑥  ∈  On 𝐵  ∈  ( 𝐴  ↑o  𝑥 )  ↔  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  On ) | 
						
							| 16 | 14 15 | sylib | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  On ) | 
						
							| 17 |  | onuni | ⊢ ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  On  →  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  On ) | 
						
							| 18 | 16 17 | syl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  On ) | 
						
							| 19 | 1 18 | eqeltrid | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝑋  ∈  On ) | 
						
							| 20 |  | sucidg | ⊢ ( 𝑋  ∈  On  →  𝑋  ∈  suc  𝑋 ) | 
						
							| 21 | 19 20 | syl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝑋  ∈  suc  𝑋 ) | 
						
							| 22 |  | suceq | ⊢ ( 𝑋  =  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  suc  𝑋  =  suc  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 23 | 1 22 | ax-mp | ⊢ suc  𝑋  =  suc  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } | 
						
							| 24 |  | dif1o | ⊢ ( 𝐵  ∈  ( On  ∖  1o )  ↔  ( 𝐵  ∈  On  ∧  𝐵  ≠  ∅ ) ) | 
						
							| 25 | 24 | simprbi | ⊢ ( 𝐵  ∈  ( On  ∖  1o )  →  𝐵  ≠  ∅ ) | 
						
							| 26 | 25 | adantl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝐵  ≠  ∅ ) | 
						
							| 27 |  | ssrab2 | ⊢ { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ⊆  On | 
						
							| 28 |  | rabn0 | ⊢ ( { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ≠  ∅  ↔  ∃ 𝑥  ∈  On 𝐵  ∈  ( 𝐴  ↑o  𝑥 ) ) | 
						
							| 29 | 14 28 | sylibr | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ≠  ∅ ) | 
						
							| 30 |  | onint | ⊢ ( ( { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ⊆  On  ∧  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ≠  ∅ )  →  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 31 | 27 29 30 | sylancr | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 32 |  | eleq1 | ⊢ ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅  →  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ↔  ∅  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) ) | 
						
							| 33 | 31 32 | syl5ibcom | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅  →  ∅  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) ) | 
						
							| 34 |  | oveq2 | ⊢ ( 𝑥  =  ∅  →  ( 𝐴  ↑o  𝑥 )  =  ( 𝐴  ↑o  ∅ ) ) | 
						
							| 35 | 34 | eleq2d | ⊢ ( 𝑥  =  ∅  →  ( 𝐵  ∈  ( 𝐴  ↑o  𝑥 )  ↔  𝐵  ∈  ( 𝐴  ↑o  ∅ ) ) ) | 
						
							| 36 | 35 | elrab | ⊢ ( ∅  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ↔  ( ∅  ∈  On  ∧  𝐵  ∈  ( 𝐴  ↑o  ∅ ) ) ) | 
						
							| 37 | 36 | simprbi | ⊢ ( ∅  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  𝐵  ∈  ( 𝐴  ↑o  ∅ ) ) | 
						
							| 38 |  | eldifi | ⊢ ( 𝐴  ∈  ( On  ∖  2o )  →  𝐴  ∈  On ) | 
						
							| 39 | 38 | adantr | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝐴  ∈  On ) | 
						
							| 40 |  | oe0 | ⊢ ( 𝐴  ∈  On  →  ( 𝐴  ↑o  ∅ )  =  1o ) | 
						
							| 41 | 39 40 | syl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( 𝐴  ↑o  ∅ )  =  1o ) | 
						
							| 42 | 41 | eleq2d | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( 𝐵  ∈  ( 𝐴  ↑o  ∅ )  ↔  𝐵  ∈  1o ) ) | 
						
							| 43 |  | el1o | ⊢ ( 𝐵  ∈  1o  ↔  𝐵  =  ∅ ) | 
						
							| 44 | 42 43 | bitrdi | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( 𝐵  ∈  ( 𝐴  ↑o  ∅ )  ↔  𝐵  =  ∅ ) ) | 
						
							| 45 | 37 44 | imbitrid | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( ∅  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  𝐵  =  ∅ ) ) | 
						
							| 46 | 33 45 | syld | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅  →  𝐵  =  ∅ ) ) | 
						
							| 47 | 46 | necon3ad | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( 𝐵  ≠  ∅  →  ¬  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅ ) ) | 
						
							| 48 | 26 47 | mpd | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ¬  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅ ) | 
						
							| 49 |  | limuni | ⊢ ( Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 50 | 49 1 | eqtr4di | ⊢ ( Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  𝑋 ) | 
						
							| 51 | 50 | adantl | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  𝑋 ) | 
						
							| 52 | 31 | adantr | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 53 | 51 52 | eqeltrrd | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  𝑋  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 54 |  | oveq2 | ⊢ ( 𝑦  =  𝑋  →  ( 𝐴  ↑o  𝑦 )  =  ( 𝐴  ↑o  𝑋 ) ) | 
						
							| 55 | 54 | eleq2d | ⊢ ( 𝑦  =  𝑋  →  ( 𝐵  ∈  ( 𝐴  ↑o  𝑦 )  ↔  𝐵  ∈  ( 𝐴  ↑o  𝑋 ) ) ) | 
						
							| 56 |  | oveq2 | ⊢ ( 𝑥  =  𝑦  →  ( 𝐴  ↑o  𝑥 )  =  ( 𝐴  ↑o  𝑦 ) ) | 
						
							| 57 | 56 | eleq2d | ⊢ ( 𝑥  =  𝑦  →  ( 𝐵  ∈  ( 𝐴  ↑o  𝑥 )  ↔  𝐵  ∈  ( 𝐴  ↑o  𝑦 ) ) ) | 
						
							| 58 | 57 | cbvrabv | ⊢ { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  { 𝑦  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑦 ) } | 
						
							| 59 | 55 58 | elrab2 | ⊢ ( 𝑋  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ↔  ( 𝑋  ∈  On  ∧  𝐵  ∈  ( 𝐴  ↑o  𝑋 ) ) ) | 
						
							| 60 | 59 | simprbi | ⊢ ( 𝑋  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  𝐵  ∈  ( 𝐴  ↑o  𝑋 ) ) | 
						
							| 61 | 53 60 | syl | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  𝐵  ∈  ( 𝐴  ↑o  𝑋 ) ) | 
						
							| 62 | 38 | ad2antrr | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  𝐴  ∈  On ) | 
						
							| 63 |  | limeq | ⊢ ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  𝑋  →  ( Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ↔  Lim  𝑋 ) ) | 
						
							| 64 | 50 63 | syl | ⊢ ( Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  ( Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ↔  Lim  𝑋 ) ) | 
						
							| 65 | 64 | ibi | ⊢ ( Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  Lim  𝑋 ) | 
						
							| 66 | 19 65 | anim12i | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  ( 𝑋  ∈  On  ∧  Lim  𝑋 ) ) | 
						
							| 67 |  | dif20el | ⊢ ( 𝐴  ∈  ( On  ∖  2o )  →  ∅  ∈  𝐴 ) | 
						
							| 68 | 67 | ad2antrr | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  ∅  ∈  𝐴 ) | 
						
							| 69 |  | oelim | ⊢ ( ( ( 𝐴  ∈  On  ∧  ( 𝑋  ∈  On  ∧  Lim  𝑋 ) )  ∧  ∅  ∈  𝐴 )  →  ( 𝐴  ↑o  𝑋 )  =  ∪  𝑦  ∈  𝑋 ( 𝐴  ↑o  𝑦 ) ) | 
						
							| 70 | 62 66 68 69 | syl21anc | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  ( 𝐴  ↑o  𝑋 )  =  ∪  𝑦  ∈  𝑋 ( 𝐴  ↑o  𝑦 ) ) | 
						
							| 71 | 61 70 | eleqtrd | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  𝐵  ∈  ∪  𝑦  ∈  𝑋 ( 𝐴  ↑o  𝑦 ) ) | 
						
							| 72 |  | eliun | ⊢ ( 𝐵  ∈  ∪  𝑦  ∈  𝑋 ( 𝐴  ↑o  𝑦 )  ↔  ∃ 𝑦  ∈  𝑋 𝐵  ∈  ( 𝐴  ↑o  𝑦 ) ) | 
						
							| 73 | 71 72 | sylib | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  ∃ 𝑦  ∈  𝑋 𝐵  ∈  ( 𝐴  ↑o  𝑦 ) ) | 
						
							| 74 | 19 | adantr | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  𝑋  ∈  On ) | 
						
							| 75 |  | onss | ⊢ ( 𝑋  ∈  On  →  𝑋  ⊆  On ) | 
						
							| 76 | 74 75 | syl | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  𝑋  ⊆  On ) | 
						
							| 77 | 76 | sselda | ⊢ ( ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  ∧  𝑦  ∈  𝑋 )  →  𝑦  ∈  On ) | 
						
							| 78 | 51 | eleq2d | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  ( 𝑦  ∈  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ↔  𝑦  ∈  𝑋 ) ) | 
						
							| 79 | 78 | biimpar | ⊢ ( ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  ∧  𝑦  ∈  𝑋 )  →  𝑦  ∈  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 80 | 57 | onnminsb | ⊢ ( 𝑦  ∈  On  →  ( 𝑦  ∈  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  ¬  𝐵  ∈  ( 𝐴  ↑o  𝑦 ) ) ) | 
						
							| 81 | 77 79 80 | sylc | ⊢ ( ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  ∧  𝑦  ∈  𝑋 )  →  ¬  𝐵  ∈  ( 𝐴  ↑o  𝑦 ) ) | 
						
							| 82 | 81 | nrexdv | ⊢ ( ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  ∧  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  →  ¬  ∃ 𝑦  ∈  𝑋 𝐵  ∈  ( 𝐴  ↑o  𝑦 ) ) | 
						
							| 83 | 73 82 | pm2.65da | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ¬  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 84 |  | ioran | ⊢ ( ¬  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅  ∨  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } )  ↔  ( ¬  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅  ∧  ¬  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) ) | 
						
							| 85 | 48 83 84 | sylanbrc | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ¬  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅  ∨  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) ) | 
						
							| 86 |  | eloni | ⊢ ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∈  On  →  Ord  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 87 |  | unizlim | ⊢ ( Ord  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ↔  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅  ∨  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) ) ) | 
						
							| 88 | 16 86 87 | 3syl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ↔  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∅  ∨  Lim  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) ) ) | 
						
							| 89 | 85 88 | mtbird | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ¬  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 90 |  | orduniorsuc | ⊢ ( Ord  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∨  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  suc  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) ) | 
						
							| 91 | 16 86 90 | 3syl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ∨  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  suc  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) ) | 
						
							| 92 | 91 | ord | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( ¬  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  suc  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) ) | 
						
							| 93 | 89 92 | mpd | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  suc  ∪  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 94 | 23 93 | eqtr4id | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  suc  𝑋  =  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 95 | 21 94 | eleqtrd | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝑋  ∈  ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 96 | 58 | inteqi | ⊢ ∩  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  =  ∩  { 𝑦  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑦 ) } | 
						
							| 97 | 95 96 | eleqtrdi | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝑋  ∈  ∩  { 𝑦  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑦 ) } ) | 
						
							| 98 | 55 | onnminsb | ⊢ ( 𝑋  ∈  On  →  ( 𝑋  ∈  ∩  { 𝑦  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑦 ) }  →  ¬  𝐵  ∈  ( 𝐴  ↑o  𝑋 ) ) ) | 
						
							| 99 | 19 97 98 | sylc | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ¬  𝐵  ∈  ( 𝐴  ↑o  𝑋 ) ) | 
						
							| 100 |  | oecl | ⊢ ( ( 𝐴  ∈  On  ∧  𝑋  ∈  On )  →  ( 𝐴  ↑o  𝑋 )  ∈  On ) | 
						
							| 101 | 39 19 100 | syl2anc | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( 𝐴  ↑o  𝑋 )  ∈  On ) | 
						
							| 102 |  | ontri1 | ⊢ ( ( ( 𝐴  ↑o  𝑋 )  ∈  On  ∧  𝐵  ∈  On )  →  ( ( 𝐴  ↑o  𝑋 )  ⊆  𝐵  ↔  ¬  𝐵  ∈  ( 𝐴  ↑o  𝑋 ) ) ) | 
						
							| 103 | 101 3 102 | syl2anc | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( ( 𝐴  ↑o  𝑋 )  ⊆  𝐵  ↔  ¬  𝐵  ∈  ( 𝐴  ↑o  𝑋 ) ) ) | 
						
							| 104 | 99 103 | mpbird | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( 𝐴  ↑o  𝑋 )  ⊆  𝐵 ) | 
						
							| 105 | 94 31 | eqeltrd | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  suc  𝑋  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) } ) | 
						
							| 106 |  | oveq2 | ⊢ ( 𝑦  =  suc  𝑋  →  ( 𝐴  ↑o  𝑦 )  =  ( 𝐴  ↑o  suc  𝑋 ) ) | 
						
							| 107 | 106 | eleq2d | ⊢ ( 𝑦  =  suc  𝑋  →  ( 𝐵  ∈  ( 𝐴  ↑o  𝑦 )  ↔  𝐵  ∈  ( 𝐴  ↑o  suc  𝑋 ) ) ) | 
						
							| 108 | 107 58 | elrab2 | ⊢ ( suc  𝑋  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  ↔  ( suc  𝑋  ∈  On  ∧  𝐵  ∈  ( 𝐴  ↑o  suc  𝑋 ) ) ) | 
						
							| 109 | 108 | simprbi | ⊢ ( suc  𝑋  ∈  { 𝑥  ∈  On  ∣  𝐵  ∈  ( 𝐴  ↑o  𝑥 ) }  →  𝐵  ∈  ( 𝐴  ↑o  suc  𝑋 ) ) | 
						
							| 110 | 105 109 | syl | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  𝐵  ∈  ( 𝐴  ↑o  suc  𝑋 ) ) | 
						
							| 111 | 19 104 110 | 3jca | ⊢ ( ( 𝐴  ∈  ( On  ∖  2o )  ∧  𝐵  ∈  ( On  ∖  1o ) )  →  ( 𝑋  ∈  On  ∧  ( 𝐴  ↑o  𝑋 )  ⊆  𝐵  ∧  𝐵  ∈  ( 𝐴  ↑o  suc  𝑋 ) ) ) |