| Step | Hyp | Ref | Expression | 
						
							| 1 |  | hbra1 | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  ∀ 𝑥 ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) | 
						
							| 2 |  | alrim3con13v | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  ∀ 𝑥 ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) )  →  ( ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )  →  ∀ 𝑥 ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 ) ) ) | 
						
							| 3 | 1 2 | e0a | ⊢ ( ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )  →  ∀ 𝑥 ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 ) ) | 
						
							| 4 |  | ax-5 | ⊢ ( 𝑥  ∈  𝐴  →  ∀ 𝑦 𝑥  ∈  𝐴 ) | 
						
							| 5 |  | hbra1 | ⊢ ( ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  ∀ 𝑦 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) | 
						
							| 6 | 4 5 | hbral | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  ∀ 𝑦 ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) | 
						
							| 7 |  | alrim3con13v | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  ∀ 𝑦 ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) )  →  ( ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )  →  ∀ 𝑦 ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 ) ) ) | 
						
							| 8 | 6 7 | e0a | ⊢ ( ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )  →  ∀ 𝑦 ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 ) ) | 
						
							| 9 |  | idn2 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ) | 
						
							| 10 |  | simpl | ⊢ ( ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )  →  𝑥  ∈  𝑦 ) | 
						
							| 11 | 9 10 | e2 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    𝑥  ∈  𝑦    ) | 
						
							| 12 |  | simpr | ⊢ ( ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )  →  𝑦  ∈  𝐵 ) | 
						
							| 13 | 9 12 | e2 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    𝑦  ∈  𝐵    ) | 
						
							| 14 |  | idn3 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ,    𝐵  ∈  𝑥    ▶    𝐵  ∈  𝑥    ) | 
						
							| 15 |  | pm3.2an3 | ⊢ ( 𝑥  ∈  𝑦  →  ( 𝑦  ∈  𝐵  →  ( 𝐵  ∈  𝑥  →  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵  ∧  𝐵  ∈  𝑥 ) ) ) ) | 
						
							| 16 | 11 13 14 15 | e223 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ,    𝐵  ∈  𝑥    ▶    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵  ∧  𝐵  ∈  𝑥 )    ) | 
						
							| 17 | 16 | in3 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    ( 𝐵  ∈  𝑥  →  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵  ∧  𝐵  ∈  𝑥 ) )    ) | 
						
							| 18 |  | en3lp | ⊢ ¬  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵  ∧  𝐵  ∈  𝑥 ) | 
						
							| 19 |  | con3 | ⊢ ( ( 𝐵  ∈  𝑥  →  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵  ∧  𝐵  ∈  𝑥 ) )  →  ( ¬  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵  ∧  𝐵  ∈  𝑥 )  →  ¬  𝐵  ∈  𝑥 ) ) | 
						
							| 20 | 17 18 19 | e20 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    ¬  𝐵  ∈  𝑥    ) | 
						
							| 21 |  | idn3 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ,    𝑥  =  𝐵    ▶    𝑥  =  𝐵    ) | 
						
							| 22 |  | eleq2 | ⊢ ( 𝑥  =  𝐵  →  ( 𝑦  ∈  𝑥  ↔  𝑦  ∈  𝐵 ) ) | 
						
							| 23 | 22 | biimprcd | ⊢ ( 𝑦  ∈  𝐵  →  ( 𝑥  =  𝐵  →  𝑦  ∈  𝑥 ) ) | 
						
							| 24 | 13 21 23 | e23 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ,    𝑥  =  𝐵    ▶    𝑦  ∈  𝑥    ) | 
						
							| 25 |  | pm3.2 | ⊢ ( 𝑥  ∈  𝑦  →  ( 𝑦  ∈  𝑥  →  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝑥 ) ) ) | 
						
							| 26 | 11 24 25 | e23 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ,    𝑥  =  𝐵    ▶    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝑥 )    ) | 
						
							| 27 | 26 | in3 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    ( 𝑥  =  𝐵  →  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝑥 ) )    ) | 
						
							| 28 |  | en2lp | ⊢ ¬  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝑥 ) | 
						
							| 29 |  | con3 | ⊢ ( ( 𝑥  =  𝐵  →  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝑥 ) )  →  ( ¬  ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝑥 )  →  ¬  𝑥  =  𝐵 ) ) | 
						
							| 30 | 27 28 29 | e20 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    ¬  𝑥  =  𝐵    ) | 
						
							| 31 |  | idn1 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ▶    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ) | 
						
							| 32 |  | simp3 | ⊢ ( ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )  →  𝐵  ∈  𝐴 ) | 
						
							| 33 | 31 32 | e1a | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ▶    𝐵  ∈  𝐴    ) | 
						
							| 34 |  | simp2 | ⊢ ( ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )  →  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) | 
						
							| 35 | 31 34 | e1a | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ▶    ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )    ) | 
						
							| 36 |  | ralcom | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ↔  ∀ 𝑦  ∈  𝐴 ∀ 𝑥  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) | 
						
							| 37 | 36 | biimpi | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  ∀ 𝑦  ∈  𝐴 ∀ 𝑥  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) | 
						
							| 38 | 35 37 | e1a | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ▶    ∀ 𝑦  ∈  𝐴 ∀ 𝑥  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )    ) | 
						
							| 39 |  | simp1 | ⊢ ( ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )  →  Tr  𝐴 ) | 
						
							| 40 | 31 39 | e1a | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ▶    Tr  𝐴    ) | 
						
							| 41 |  | trel | ⊢ ( Tr  𝐴  →  ( ( 𝑦  ∈  𝐵  ∧  𝐵  ∈  𝐴 )  →  𝑦  ∈  𝐴 ) ) | 
						
							| 42 | 41 | expd | ⊢ ( Tr  𝐴  →  ( 𝑦  ∈  𝐵  →  ( 𝐵  ∈  𝐴  →  𝑦  ∈  𝐴 ) ) ) | 
						
							| 43 | 40 13 33 42 | e121 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    𝑦  ∈  𝐴    ) | 
						
							| 44 |  | trel | ⊢ ( Tr  𝐴  →  ( ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐴 )  →  𝑥  ∈  𝐴 ) ) | 
						
							| 45 | 44 | expd | ⊢ ( Tr  𝐴  →  ( 𝑥  ∈  𝑦  →  ( 𝑦  ∈  𝐴  →  𝑥  ∈  𝐴 ) ) ) | 
						
							| 46 | 40 11 43 45 | e122 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    𝑥  ∈  𝐴    ) | 
						
							| 47 |  | rspsbc2 | ⊢ ( 𝐵  ∈  𝐴  →  ( 𝑥  ∈  𝐴  →  ( ∀ 𝑦  ∈  𝐴 ∀ 𝑥  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  [ 𝑥  /  𝑥 ] [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) ) ) | 
						
							| 48 | 47 | com13 | ⊢ ( ∀ 𝑦  ∈  𝐴 ∀ 𝑥  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  ( 𝑥  ∈  𝐴  →  ( 𝐵  ∈  𝐴  →  [ 𝑥  /  𝑥 ] [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) ) ) | 
						
							| 49 | 38 46 33 48 | e121 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    [ 𝑥  /  𝑥 ] [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )    ) | 
						
							| 50 |  | equid | ⊢ 𝑥  =  𝑥 | 
						
							| 51 |  | sbceq2a | ⊢ ( 𝑥  =  𝑥  →  ( [ 𝑥  /  𝑥 ] [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ↔  [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) ) | 
						
							| 52 | 50 51 | ax-mp | ⊢ ( [ 𝑥  /  𝑥 ] [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ↔  [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) | 
						
							| 53 | 52 | biimpi | ⊢ ( [ 𝑥  /  𝑥 ] [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 ) ) | 
						
							| 54 | 49 53 | e2 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )    ) | 
						
							| 55 |  | sbcoreleleq | ⊢ ( 𝐵  ∈  𝐴  →  ( [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ↔  ( 𝑥  ∈  𝐵  ∨  𝐵  ∈  𝑥  ∨  𝑥  =  𝐵 ) ) ) | 
						
							| 56 | 55 | biimpd | ⊢ ( 𝐵  ∈  𝐴  →  ( [ 𝐵  /  𝑦 ] ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  →  ( 𝑥  ∈  𝐵  ∨  𝐵  ∈  𝑥  ∨  𝑥  =  𝐵 ) ) ) | 
						
							| 57 | 33 54 56 | e12 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    ( 𝑥  ∈  𝐵  ∨  𝐵  ∈  𝑥  ∨  𝑥  =  𝐵 )    ) | 
						
							| 58 |  | 3ornot23 | ⊢ ( ( ¬  𝐵  ∈  𝑥  ∧  ¬  𝑥  =  𝐵 )  →  ( ( 𝑥  ∈  𝐵  ∨  𝐵  ∈  𝑥  ∨  𝑥  =  𝐵 )  →  𝑥  ∈  𝐵 ) ) | 
						
							| 59 | 58 | ex | ⊢ ( ¬  𝐵  ∈  𝑥  →  ( ¬  𝑥  =  𝐵  →  ( ( 𝑥  ∈  𝐵  ∨  𝐵  ∈  𝑥  ∨  𝑥  =  𝐵 )  →  𝑥  ∈  𝐵 ) ) ) | 
						
							| 60 | 20 30 57 59 | e222 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ,    ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )    ▶    𝑥  ∈  𝐵    ) | 
						
							| 61 | 60 | in2 | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ▶    ( ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )  →  𝑥  ∈  𝐵 )    ) | 
						
							| 62 | 8 61 | gen11nv | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ▶    ∀ 𝑦 ( ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )  →  𝑥  ∈  𝐵 )    ) | 
						
							| 63 | 3 62 | gen11nv | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ▶    ∀ 𝑥 ∀ 𝑦 ( ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )  →  𝑥  ∈  𝐵 )    ) | 
						
							| 64 |  | dftr2 | ⊢ ( Tr  𝐵  ↔  ∀ 𝑥 ∀ 𝑦 ( ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )  →  𝑥  ∈  𝐵 ) ) | 
						
							| 65 | 64 | biimpri | ⊢ ( ∀ 𝑥 ∀ 𝑦 ( ( 𝑥  ∈  𝑦  ∧  𝑦  ∈  𝐵 )  →  𝑥  ∈  𝐵 )  →  Tr  𝐵 ) | 
						
							| 66 | 63 65 | e1a | ⊢ (    ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )    ▶    Tr  𝐵    ) | 
						
							| 67 | 66 | in1 | ⊢ ( ( Tr  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥  ∈  𝑦  ∨  𝑦  ∈  𝑥  ∨  𝑥  =  𝑦 )  ∧  𝐵  ∈  𝐴 )  →  Tr  𝐵 ) |