| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							tcvalg | 
							⊢ ( 𝐴  ∈  𝑉  →  ( TC ‘ 𝐴 )  =  ∩  { 𝑥  ∣  ( 𝐴  ⊆  𝑥  ∧  Tr  𝑥 ) } )  | 
						
						
							| 2 | 
							
								
							 | 
							fvex | 
							⊢ ( TC ‘ 𝐴 )  ∈  V  | 
						
						
							| 3 | 
							
								1 2
							 | 
							eqeltrrdi | 
							⊢ ( 𝐴  ∈  𝑉  →  ∩  { 𝑥  ∣  ( 𝐴  ⊆  𝑥  ∧  Tr  𝑥 ) }  ∈  V )  | 
						
						
							| 4 | 
							
								
							 | 
							intexab | 
							⊢ ( ∃ 𝑥 ( 𝐴  ⊆  𝑥  ∧  Tr  𝑥 )  ↔  ∩  { 𝑥  ∣  ( 𝐴  ⊆  𝑥  ∧  Tr  𝑥 ) }  ∈  V )  | 
						
						
							| 5 | 
							
								3 4
							 | 
							sylibr | 
							⊢ ( 𝐴  ∈  𝑉  →  ∃ 𝑥 ( 𝐴  ⊆  𝑥  ∧  Tr  𝑥 ) )  | 
						
						
							| 6 | 
							
								
							 | 
							ssin | 
							⊢ ( ( 𝐴  ⊆  𝑥  ∧  𝐴  ⊆  𝐵 )  ↔  𝐴  ⊆  ( 𝑥  ∩  𝐵 ) )  | 
						
						
							| 7 | 
							
								6
							 | 
							biimpi | 
							⊢ ( ( 𝐴  ⊆  𝑥  ∧  𝐴  ⊆  𝐵 )  →  𝐴  ⊆  ( 𝑥  ∩  𝐵 ) )  | 
						
						
							| 8 | 
							
								
							 | 
							trin | 
							⊢ ( ( Tr  𝑥  ∧  Tr  𝐵 )  →  Tr  ( 𝑥  ∩  𝐵 ) )  | 
						
						
							| 9 | 
							
								7 8
							 | 
							anim12i | 
							⊢ ( ( ( 𝐴  ⊆  𝑥  ∧  𝐴  ⊆  𝐵 )  ∧  ( Tr  𝑥  ∧  Tr  𝐵 ) )  →  ( 𝐴  ⊆  ( 𝑥  ∩  𝐵 )  ∧  Tr  ( 𝑥  ∩  𝐵 ) ) )  | 
						
						
							| 10 | 
							
								9
							 | 
							an4s | 
							⊢ ( ( ( 𝐴  ⊆  𝑥  ∧  Tr  𝑥 )  ∧  ( 𝐴  ⊆  𝐵  ∧  Tr  𝐵 ) )  →  ( 𝐴  ⊆  ( 𝑥  ∩  𝐵 )  ∧  Tr  ( 𝑥  ∩  𝐵 ) ) )  | 
						
						
							| 11 | 
							
								10
							 | 
							expcom | 
							⊢ ( ( 𝐴  ⊆  𝐵  ∧  Tr  𝐵 )  →  ( ( 𝐴  ⊆  𝑥  ∧  Tr  𝑥 )  →  ( 𝐴  ⊆  ( 𝑥  ∩  𝐵 )  ∧  Tr  ( 𝑥  ∩  𝐵 ) ) ) )  | 
						
						
							| 12 | 
							
								
							 | 
							vex | 
							⊢ 𝑥  ∈  V  | 
						
						
							| 13 | 
							
								12
							 | 
							inex1 | 
							⊢ ( 𝑥  ∩  𝐵 )  ∈  V  | 
						
						
							| 14 | 
							
								
							 | 
							sseq2 | 
							⊢ ( 𝑦  =  ( 𝑥  ∩  𝐵 )  →  ( 𝐴  ⊆  𝑦  ↔  𝐴  ⊆  ( 𝑥  ∩  𝐵 ) ) )  | 
						
						
							| 15 | 
							
								
							 | 
							treq | 
							⊢ ( 𝑦  =  ( 𝑥  ∩  𝐵 )  →  ( Tr  𝑦  ↔  Tr  ( 𝑥  ∩  𝐵 ) ) )  | 
						
						
							| 16 | 
							
								14 15
							 | 
							anbi12d | 
							⊢ ( 𝑦  =  ( 𝑥  ∩  𝐵 )  →  ( ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 )  ↔  ( 𝐴  ⊆  ( 𝑥  ∩  𝐵 )  ∧  Tr  ( 𝑥  ∩  𝐵 ) ) ) )  | 
						
						
							| 17 | 
							
								13 16
							 | 
							elab | 
							⊢ ( ( 𝑥  ∩  𝐵 )  ∈  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) }  ↔  ( 𝐴  ⊆  ( 𝑥  ∩  𝐵 )  ∧  Tr  ( 𝑥  ∩  𝐵 ) ) )  | 
						
						
							| 18 | 
							
								
							 | 
							intss1 | 
							⊢ ( ( 𝑥  ∩  𝐵 )  ∈  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) }  →  ∩  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) }  ⊆  ( 𝑥  ∩  𝐵 ) )  | 
						
						
							| 19 | 
							
								17 18
							 | 
							sylbir | 
							⊢ ( ( 𝐴  ⊆  ( 𝑥  ∩  𝐵 )  ∧  Tr  ( 𝑥  ∩  𝐵 ) )  →  ∩  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) }  ⊆  ( 𝑥  ∩  𝐵 ) )  | 
						
						
							| 20 | 
							
								
							 | 
							inss2 | 
							⊢ ( 𝑥  ∩  𝐵 )  ⊆  𝐵  | 
						
						
							| 21 | 
							
								19 20
							 | 
							sstrdi | 
							⊢ ( ( 𝐴  ⊆  ( 𝑥  ∩  𝐵 )  ∧  Tr  ( 𝑥  ∩  𝐵 ) )  →  ∩  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) }  ⊆  𝐵 )  | 
						
						
							| 22 | 
							
								11 21
							 | 
							syl6 | 
							⊢ ( ( 𝐴  ⊆  𝐵  ∧  Tr  𝐵 )  →  ( ( 𝐴  ⊆  𝑥  ∧  Tr  𝑥 )  →  ∩  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) }  ⊆  𝐵 ) )  | 
						
						
							| 23 | 
							
								22
							 | 
							exlimdv | 
							⊢ ( ( 𝐴  ⊆  𝐵  ∧  Tr  𝐵 )  →  ( ∃ 𝑥 ( 𝐴  ⊆  𝑥  ∧  Tr  𝑥 )  →  ∩  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) }  ⊆  𝐵 ) )  | 
						
						
							| 24 | 
							
								5 23
							 | 
							syl5com | 
							⊢ ( 𝐴  ∈  𝑉  →  ( ( 𝐴  ⊆  𝐵  ∧  Tr  𝐵 )  →  ∩  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) }  ⊆  𝐵 ) )  | 
						
						
							| 25 | 
							
								
							 | 
							tcvalg | 
							⊢ ( 𝐴  ∈  𝑉  →  ( TC ‘ 𝐴 )  =  ∩  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) } )  | 
						
						
							| 26 | 
							
								25
							 | 
							sseq1d | 
							⊢ ( 𝐴  ∈  𝑉  →  ( ( TC ‘ 𝐴 )  ⊆  𝐵  ↔  ∩  { 𝑦  ∣  ( 𝐴  ⊆  𝑦  ∧  Tr  𝑦 ) }  ⊆  𝐵 ) )  | 
						
						
							| 27 | 
							
								24 26
							 | 
							sylibrd | 
							⊢ ( 𝐴  ∈  𝑉  →  ( ( 𝐴  ⊆  𝐵  ∧  Tr  𝐵 )  →  ( TC ‘ 𝐴 )  ⊆  𝐵 ) )  |