| Step | Hyp | Ref | Expression | 
						
							| 1 |  | vex | ⊢ 𝑥  ∈  V | 
						
							| 2 |  | dfon2lem3 | ⊢ ( 𝑥  ∈  V  →  ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  ( Tr  𝑥  ∧  ∀ 𝑧  ∈  𝑥 ¬  𝑧  ∈  𝑧 ) ) ) | 
						
							| 3 | 1 2 | ax-mp | ⊢ ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  ( Tr  𝑥  ∧  ∀ 𝑧  ∈  𝑥 ¬  𝑧  ∈  𝑧 ) ) | 
						
							| 4 | 3 | simpld | ⊢ ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  Tr  𝑥 ) | 
						
							| 5 | 4 | ralimi | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  ∀ 𝑥  ∈  𝐴 Tr  𝑥 ) | 
						
							| 6 |  | trint | ⊢ ( ∀ 𝑥  ∈  𝐴 Tr  𝑥  →  Tr  ∩  𝐴 ) | 
						
							| 7 | 5 6 | syl | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  Tr  ∩  𝐴 ) | 
						
							| 8 | 7 | adantl | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  Tr  ∩  𝐴 ) | 
						
							| 9 | 1 | dfon2lem7 | ⊢ ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 10 | 9 | alrimiv | ⊢ ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  ∀ 𝑤 ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 11 | 10 | ralimi | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  ∀ 𝑥  ∈  𝐴 ∀ 𝑤 ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 12 |  | df-ral | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑤 ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ∀ 𝑥 ( 𝑥  ∈  𝐴  →  ∀ 𝑤 ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) ) | 
						
							| 13 |  | 19.21v | ⊢ ( ∀ 𝑤 ( 𝑥  ∈  𝐴  →  ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) )  ↔  ( 𝑥  ∈  𝐴  →  ∀ 𝑤 ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) ) | 
						
							| 14 | 13 | albii | ⊢ ( ∀ 𝑥 ∀ 𝑤 ( 𝑥  ∈  𝐴  →  ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) )  ↔  ∀ 𝑥 ( 𝑥  ∈  𝐴  →  ∀ 𝑤 ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) ) | 
						
							| 15 | 12 14 | bitr4i | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑤 ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ∀ 𝑥 ∀ 𝑤 ( 𝑥  ∈  𝐴  →  ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) ) | 
						
							| 16 |  | impexp | ⊢ ( ( ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ( 𝑥  ∈  𝐴  →  ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) ) | 
						
							| 17 | 16 | 2albii | ⊢ ( ∀ 𝑥 ∀ 𝑤 ( ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ∀ 𝑥 ∀ 𝑤 ( 𝑥  ∈  𝐴  →  ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) ) | 
						
							| 18 |  | eluni2 | ⊢ ( 𝑤  ∈  ∪  𝐴  ↔  ∃ 𝑥  ∈  𝐴 𝑤  ∈  𝑥 ) | 
						
							| 19 | 18 | biimpi | ⊢ ( 𝑤  ∈  ∪  𝐴  →  ∃ 𝑥  ∈  𝐴 𝑤  ∈  𝑥 ) | 
						
							| 20 | 19 | imim1i | ⊢ ( ( ∃ 𝑥  ∈  𝐴 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  →  ( 𝑤  ∈  ∪  𝐴  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 21 | 20 | alimi | ⊢ ( ∀ 𝑤 ( ∃ 𝑥  ∈  𝐴 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  →  ∀ 𝑤 ( 𝑤  ∈  ∪  𝐴  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 22 |  | alcom | ⊢ ( ∀ 𝑥 ∀ 𝑤 ( ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ∀ 𝑤 ∀ 𝑥 ( ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 23 |  | 19.23v | ⊢ ( ∀ 𝑥 ( ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ( ∃ 𝑥 ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 24 |  | df-rex | ⊢ ( ∃ 𝑥  ∈  𝐴 𝑤  ∈  𝑥  ↔  ∃ 𝑥 ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 ) ) | 
						
							| 25 | 24 | imbi1i | ⊢ ( ( ∃ 𝑥  ∈  𝐴 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ( ∃ 𝑥 ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 26 | 23 25 | bitr4i | ⊢ ( ∀ 𝑥 ( ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ( ∃ 𝑥  ∈  𝐴 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 27 | 26 | albii | ⊢ ( ∀ 𝑤 ∀ 𝑥 ( ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ∀ 𝑤 ( ∃ 𝑥  ∈  𝐴 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 28 | 22 27 | bitri | ⊢ ( ∀ 𝑥 ∀ 𝑤 ( ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  ↔  ∀ 𝑤 ( ∃ 𝑥  ∈  𝐴 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 29 |  | df-ral | ⊢ ( ∀ 𝑤  ∈  ∪  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 )  ↔  ∀ 𝑤 ( 𝑤  ∈  ∪  𝐴  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 30 | 21 28 29 | 3imtr4i | ⊢ ( ∀ 𝑥 ∀ 𝑤 ( ( 𝑥  ∈  𝐴  ∧  𝑤  ∈  𝑥 )  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  →  ∀ 𝑤  ∈  ∪  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) | 
						
							| 31 | 17 30 | sylbir | ⊢ ( ∀ 𝑥 ∀ 𝑤 ( 𝑥  ∈  𝐴  →  ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) )  →  ∀ 𝑤  ∈  ∪  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) | 
						
							| 32 | 15 31 | sylbi | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑤 ( 𝑤  ∈  𝑥  →  ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  →  ∀ 𝑤  ∈  ∪  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) | 
						
							| 33 | 11 32 | syl | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  ∀ 𝑤  ∈  ∪  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) | 
						
							| 34 | 33 | adantl | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ∀ 𝑤  ∈  ∪  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) | 
						
							| 35 |  | intssuni | ⊢ ( 𝐴  ≠  ∅  →  ∩  𝐴  ⊆  ∪  𝐴 ) | 
						
							| 36 |  | ssralv | ⊢ ( ∩  𝐴  ⊆  ∪  𝐴  →  ( ∀ 𝑤  ∈  ∪  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 )  →  ∀ 𝑤  ∈  ∩  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 37 | 35 36 | syl | ⊢ ( 𝐴  ≠  ∅  →  ( ∀ 𝑤  ∈  ∪  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 )  →  ∀ 𝑤  ∈  ∩  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 38 | 37 | adantr | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ( ∀ 𝑤  ∈  ∪  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 )  →  ∀ 𝑤  ∈  ∩  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) ) | 
						
							| 39 | 34 38 | mpd | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ∀ 𝑤  ∈  ∩  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) ) | 
						
							| 40 |  | dfon2lem6 | ⊢ ( ( Tr  ∩  𝐴  ∧  ∀ 𝑤  ∈  ∩  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  →  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) ) | 
						
							| 41 |  | intex | ⊢ ( 𝐴  ≠  ∅  ↔  ∩  𝐴  ∈  V ) | 
						
							| 42 |  | dfon2lem3 | ⊢ ( ∩  𝐴  ∈  V  →  ( ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 )  →  ( Tr  ∩  𝐴  ∧  ∀ 𝑡  ∈  ∩  𝐴 ¬  𝑡  ∈  𝑡 ) ) ) | 
						
							| 43 | 41 42 | sylbi | ⊢ ( 𝐴  ≠  ∅  →  ( ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 )  →  ( Tr  ∩  𝐴  ∧  ∀ 𝑡  ∈  ∩  𝐴 ¬  𝑡  ∈  𝑡 ) ) ) | 
						
							| 44 | 43 | imp | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ( Tr  ∩  𝐴  ∧  ∀ 𝑡  ∈  ∩  𝐴 ¬  𝑡  ∈  𝑡 ) ) | 
						
							| 45 | 44 | simprd | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ∀ 𝑡  ∈  ∩  𝐴 ¬  𝑡  ∈  𝑡 ) | 
						
							| 46 |  | untelirr | ⊢ ( ∀ 𝑡  ∈  ∩  𝐴 ¬  𝑡  ∈  𝑡  →  ¬  ∩  𝐴  ∈  ∩  𝐴 ) | 
						
							| 47 | 45 46 | syl | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ¬  ∩  𝐴  ∈  ∩  𝐴 ) | 
						
							| 48 | 47 | adantlr | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ¬  ∩  𝐴  ∈  ∩  𝐴 ) | 
						
							| 49 |  | risset | ⊢ ( ∩  𝐴  ∈  𝐴  ↔  ∃ 𝑡  ∈  𝐴 𝑡  =  ∩  𝐴 ) | 
						
							| 50 | 49 | notbii | ⊢ ( ¬  ∩  𝐴  ∈  𝐴  ↔  ¬  ∃ 𝑡  ∈  𝐴 𝑡  =  ∩  𝐴 ) | 
						
							| 51 |  | ralnex | ⊢ ( ∀ 𝑡  ∈  𝐴 ¬  𝑡  =  ∩  𝐴  ↔  ¬  ∃ 𝑡  ∈  𝐴 𝑡  =  ∩  𝐴 ) | 
						
							| 52 | 50 51 | bitr4i | ⊢ ( ¬  ∩  𝐴  ∈  𝐴  ↔  ∀ 𝑡  ∈  𝐴 ¬  𝑡  =  ∩  𝐴 ) | 
						
							| 53 |  | eqcom | ⊢ ( 𝑡  =  ∩  𝐴  ↔  ∩  𝐴  =  𝑡 ) | 
						
							| 54 | 53 | notbii | ⊢ ( ¬  𝑡  =  ∩  𝐴  ↔  ¬  ∩  𝐴  =  𝑡 ) | 
						
							| 55 | 44 | simpld | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  Tr  ∩  𝐴 ) | 
						
							| 56 | 55 | adantlr | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  Tr  ∩  𝐴 ) | 
						
							| 57 |  | psseq2 | ⊢ ( 𝑥  =  𝑡  →  ( 𝑦  ⊊  𝑥  ↔  𝑦  ⊊  𝑡 ) ) | 
						
							| 58 | 57 | anbi1d | ⊢ ( 𝑥  =  𝑡  →  ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  ↔  ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 ) ) ) | 
						
							| 59 |  | elequ2 | ⊢ ( 𝑥  =  𝑡  →  ( 𝑦  ∈  𝑥  ↔  𝑦  ∈  𝑡 ) ) | 
						
							| 60 | 58 59 | imbi12d | ⊢ ( 𝑥  =  𝑡  →  ( ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  ↔  ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 ) ) ) | 
						
							| 61 | 60 | albidv | ⊢ ( 𝑥  =  𝑡  →  ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  ↔  ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 ) ) ) | 
						
							| 62 | 61 | rspccv | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 )  →  ( 𝑡  ∈  𝐴  →  ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 ) ) ) | 
						
							| 63 | 62 | adantl | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ( 𝑡  ∈  𝐴  →  ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 ) ) ) | 
						
							| 64 |  | intss1 | ⊢ ( 𝑡  ∈  𝐴  →  ∩  𝐴  ⊆  𝑡 ) | 
						
							| 65 |  | dfpss2 | ⊢ ( ∩  𝐴  ⊊  𝑡  ↔  ( ∩  𝐴  ⊆  𝑡  ∧  ¬  ∩  𝐴  =  𝑡 ) ) | 
						
							| 66 |  | psseq1 | ⊢ ( 𝑦  =  ∩  𝐴  →  ( 𝑦  ⊊  𝑡  ↔  ∩  𝐴  ⊊  𝑡 ) ) | 
						
							| 67 |  | treq | ⊢ ( 𝑦  =  ∩  𝐴  →  ( Tr  𝑦  ↔  Tr  ∩  𝐴 ) ) | 
						
							| 68 | 66 67 | anbi12d | ⊢ ( 𝑦  =  ∩  𝐴  →  ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  ↔  ( ∩  𝐴  ⊊  𝑡  ∧  Tr  ∩  𝐴 ) ) ) | 
						
							| 69 |  | eleq1 | ⊢ ( 𝑦  =  ∩  𝐴  →  ( 𝑦  ∈  𝑡  ↔  ∩  𝐴  ∈  𝑡 ) ) | 
						
							| 70 | 68 69 | imbi12d | ⊢ ( 𝑦  =  ∩  𝐴  →  ( ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 )  ↔  ( ( ∩  𝐴  ⊊  𝑡  ∧  Tr  ∩  𝐴 )  →  ∩  𝐴  ∈  𝑡 ) ) ) | 
						
							| 71 | 70 | spcgv | ⊢ ( ∩  𝐴  ∈  V  →  ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 )  →  ( ( ∩  𝐴  ⊊  𝑡  ∧  Tr  ∩  𝐴 )  →  ∩  𝐴  ∈  𝑡 ) ) ) | 
						
							| 72 | 41 71 | sylbi | ⊢ ( 𝐴  ≠  ∅  →  ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 )  →  ( ( ∩  𝐴  ⊊  𝑡  ∧  Tr  ∩  𝐴 )  →  ∩  𝐴  ∈  𝑡 ) ) ) | 
						
							| 73 | 72 | imp | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 ) )  →  ( ( ∩  𝐴  ⊊  𝑡  ∧  Tr  ∩  𝐴 )  →  ∩  𝐴  ∈  𝑡 ) ) | 
						
							| 74 | 73 | expd | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 ) )  →  ( ∩  𝐴  ⊊  𝑡  →  ( Tr  ∩  𝐴  →  ∩  𝐴  ∈  𝑡 ) ) ) | 
						
							| 75 | 65 74 | biimtrrid | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 ) )  →  ( ( ∩  𝐴  ⊆  𝑡  ∧  ¬  ∩  𝐴  =  𝑡 )  →  ( Tr  ∩  𝐴  →  ∩  𝐴  ∈  𝑡 ) ) ) | 
						
							| 76 | 75 | exp4b | ⊢ ( 𝐴  ≠  ∅  →  ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 )  →  ( ∩  𝐴  ⊆  𝑡  →  ( ¬  ∩  𝐴  =  𝑡  →  ( Tr  ∩  𝐴  →  ∩  𝐴  ∈  𝑡 ) ) ) ) ) | 
						
							| 77 | 76 | com45 | ⊢ ( 𝐴  ≠  ∅  →  ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 )  →  ( ∩  𝐴  ⊆  𝑡  →  ( Tr  ∩  𝐴  →  ( ¬  ∩  𝐴  =  𝑡  →  ∩  𝐴  ∈  𝑡 ) ) ) ) ) | 
						
							| 78 | 77 | com23 | ⊢ ( 𝐴  ≠  ∅  →  ( ∩  𝐴  ⊆  𝑡  →  ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 )  →  ( Tr  ∩  𝐴  →  ( ¬  ∩  𝐴  =  𝑡  →  ∩  𝐴  ∈  𝑡 ) ) ) ) ) | 
						
							| 79 | 64 78 | syl5 | ⊢ ( 𝐴  ≠  ∅  →  ( 𝑡  ∈  𝐴  →  ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 )  →  ( Tr  ∩  𝐴  →  ( ¬  ∩  𝐴  =  𝑡  →  ∩  𝐴  ∈  𝑡 ) ) ) ) ) | 
						
							| 80 | 79 | adantr | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ( 𝑡  ∈  𝐴  →  ( ∀ 𝑦 ( ( 𝑦  ⊊  𝑡  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑡 )  →  ( Tr  ∩  𝐴  →  ( ¬  ∩  𝐴  =  𝑡  →  ∩  𝐴  ∈  𝑡 ) ) ) ) ) | 
						
							| 81 | 63 80 | mpdd | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ( 𝑡  ∈  𝐴  →  ( Tr  ∩  𝐴  →  ( ¬  ∩  𝐴  =  𝑡  →  ∩  𝐴  ∈  𝑡 ) ) ) ) | 
						
							| 82 | 81 | adantr | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ( 𝑡  ∈  𝐴  →  ( Tr  ∩  𝐴  →  ( ¬  ∩  𝐴  =  𝑡  →  ∩  𝐴  ∈  𝑡 ) ) ) ) | 
						
							| 83 | 56 82 | mpid | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ( 𝑡  ∈  𝐴  →  ( ¬  ∩  𝐴  =  𝑡  →  ∩  𝐴  ∈  𝑡 ) ) ) | 
						
							| 84 | 54 83 | syl7bi | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ( 𝑡  ∈  𝐴  →  ( ¬  𝑡  =  ∩  𝐴  →  ∩  𝐴  ∈  𝑡 ) ) ) | 
						
							| 85 | 84 | ralrimiv | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ∀ 𝑡  ∈  𝐴 ( ¬  𝑡  =  ∩  𝐴  →  ∩  𝐴  ∈  𝑡 ) ) | 
						
							| 86 |  | ralim | ⊢ ( ∀ 𝑡  ∈  𝐴 ( ¬  𝑡  =  ∩  𝐴  →  ∩  𝐴  ∈  𝑡 )  →  ( ∀ 𝑡  ∈  𝐴 ¬  𝑡  =  ∩  𝐴  →  ∀ 𝑡  ∈  𝐴 ∩  𝐴  ∈  𝑡 ) ) | 
						
							| 87 | 85 86 | syl | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ( ∀ 𝑡  ∈  𝐴 ¬  𝑡  =  ∩  𝐴  →  ∀ 𝑡  ∈  𝐴 ∩  𝐴  ∈  𝑡 ) ) | 
						
							| 88 | 52 87 | biimtrid | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ( ¬  ∩  𝐴  ∈  𝐴  →  ∀ 𝑡  ∈  𝐴 ∩  𝐴  ∈  𝑡 ) ) | 
						
							| 89 |  | elintg | ⊢ ( ∩  𝐴  ∈  V  →  ( ∩  𝐴  ∈  ∩  𝐴  ↔  ∀ 𝑡  ∈  𝐴 ∩  𝐴  ∈  𝑡 ) ) | 
						
							| 90 | 41 89 | sylbi | ⊢ ( 𝐴  ≠  ∅  →  ( ∩  𝐴  ∈  ∩  𝐴  ↔  ∀ 𝑡  ∈  𝐴 ∩  𝐴  ∈  𝑡 ) ) | 
						
							| 91 | 90 | ad2antrr | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ( ∩  𝐴  ∈  ∩  𝐴  ↔  ∀ 𝑡  ∈  𝐴 ∩  𝐴  ∈  𝑡 ) ) | 
						
							| 92 | 88 91 | sylibrd | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ( ¬  ∩  𝐴  ∈  𝐴  →  ∩  𝐴  ∈  ∩  𝐴 ) ) | 
						
							| 93 | 48 92 | mt3d | ⊢ ( ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  ∧  ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 ) )  →  ∩  𝐴  ∈  𝐴 ) | 
						
							| 94 | 93 | ex | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ( ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 )  →  ∩  𝐴  ∈  𝐴 ) ) | 
						
							| 95 | 94 | ancld | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ( ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 )  →  ( ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 )  ∧  ∩  𝐴  ∈  𝐴 ) ) ) | 
						
							| 96 | 40 95 | syl5 | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ( ( Tr  ∩  𝐴  ∧  ∀ 𝑤  ∈  ∩  𝐴 ∀ 𝑡 ( ( 𝑡  ⊊  𝑤  ∧  Tr  𝑡 )  →  𝑡  ∈  𝑤 ) )  →  ( ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 )  ∧  ∩  𝐴  ∈  𝐴 ) ) ) | 
						
							| 97 | 8 39 96 | mp2and | ⊢ ( ( 𝐴  ≠  ∅  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦 ( ( 𝑦  ⊊  𝑥  ∧  Tr  𝑦 )  →  𝑦  ∈  𝑥 ) )  →  ( ∀ 𝑧 ( ( 𝑧  ⊊  ∩  𝐴  ∧  Tr  𝑧 )  →  𝑧  ∈  ∩  𝐴 )  ∧  ∩  𝐴  ∈  𝐴 ) ) |