| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							setc1strwun.s | 
							⊢ 𝑆  =  ( SetCat ‘ 𝑈 )  | 
						
						
							| 2 | 
							
								
							 | 
							setc1strwun.c | 
							⊢ 𝐶  =  ( Base ‘ 𝑆 )  | 
						
						
							| 3 | 
							
								
							 | 
							setc1strwun.u | 
							⊢ ( 𝜑  →  𝑈  ∈  WUni )  | 
						
						
							| 4 | 
							
								
							 | 
							setc1strwun.o | 
							⊢ ( 𝜑  →  ω  ∈  𝑈 )  | 
						
						
							| 5 | 
							
								1 3
							 | 
							setcbas | 
							⊢ ( 𝜑  →  𝑈  =  ( Base ‘ 𝑆 ) )  | 
						
						
							| 6 | 
							
								2 5
							 | 
							eqtr4id | 
							⊢ ( 𝜑  →  𝐶  =  𝑈 )  | 
						
						
							| 7 | 
							
								6
							 | 
							eleq2d | 
							⊢ ( 𝜑  →  ( 𝑋  ∈  𝐶  ↔  𝑋  ∈  𝑈 ) )  | 
						
						
							| 8 | 
							
								7
							 | 
							biimpa | 
							⊢ ( ( 𝜑  ∧  𝑋  ∈  𝐶 )  →  𝑋  ∈  𝑈 )  | 
						
						
							| 9 | 
							
								
							 | 
							eqid | 
							⊢ { 〈 ( Base ‘ ndx ) ,  𝑋 〉 }  =  { 〈 ( Base ‘ ndx ) ,  𝑋 〉 }  | 
						
						
							| 10 | 
							
								9 3 4
							 | 
							1strwun | 
							⊢ ( ( 𝜑  ∧  𝑋  ∈  𝑈 )  →  { 〈 ( Base ‘ ndx ) ,  𝑋 〉 }  ∈  𝑈 )  | 
						
						
							| 11 | 
							
								8 10
							 | 
							syldan | 
							⊢ ( ( 𝜑  ∧  𝑋  ∈  𝐶 )  →  { 〈 ( Base ‘ ndx ) ,  𝑋 〉 }  ∈  𝑈 )  |