| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj1097.1 | 
							⊢ ( 𝜑  ↔  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 2 | 
							
								
							 | 
							bnj1097.3 | 
							⊢ ( 𝜒  ↔  ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 3 | 
							
								
							 | 
							bnj1097.5 | 
							⊢ ( 𝜏  ↔  ( 𝐵  ∈  V  ∧   TrFo ( 𝐵 ,  𝐴 ,  𝑅 )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 ) )  | 
						
						
							| 4 | 
							
								1
							 | 
							biimpi | 
							⊢ ( 𝜑  →  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 5 | 
							
								2 4
							 | 
							bnj771 | 
							⊢ ( 𝜒  →  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 6 | 
							
								5
							 | 
							3ad2ant3 | 
							⊢ ( ( 𝜃  ∧  𝜏  ∧  𝜒 )  →  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 7 | 
							
								6
							 | 
							adantr | 
							⊢ ( ( ( 𝜃  ∧  𝜏  ∧  𝜒 )  ∧  𝜑0 )  →  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 8 | 
							
								3
							 | 
							simp3bi | 
							⊢ ( 𝜏  →   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 )  | 
						
						
							| 9 | 
							
								8
							 | 
							3ad2ant2 | 
							⊢ ( ( 𝜃  ∧  𝜏  ∧  𝜒 )  →   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 )  | 
						
						
							| 10 | 
							
								9
							 | 
							adantr | 
							⊢ ( ( ( 𝜃  ∧  𝜏  ∧  𝜒 )  ∧  𝜑0 )  →   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 )  | 
						
						
							| 11 | 
							
								7 10
							 | 
							jca | 
							⊢ ( ( ( 𝜃  ∧  𝜏  ∧  𝜒 )  ∧  𝜑0 )  →  ( ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 ) )  | 
						
						
							| 12 | 
							
								11
							 | 
							anim2i | 
							⊢ ( ( 𝑖  =  ∅  ∧  ( ( 𝜃  ∧  𝜏  ∧  𝜒 )  ∧  𝜑0 ) )  →  ( 𝑖  =  ∅  ∧  ( ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 ) ) )  | 
						
						
							| 13 | 
							
								
							 | 
							3anass | 
							⊢ ( ( 𝑖  =  ∅  ∧  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 )  ↔  ( 𝑖  =  ∅  ∧  ( ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 ) ) )  | 
						
						
							| 14 | 
							
								12 13
							 | 
							sylibr | 
							⊢ ( ( 𝑖  =  ∅  ∧  ( ( 𝜃  ∧  𝜏  ∧  𝜒 )  ∧  𝜑0 ) )  →  ( 𝑖  =  ∅  ∧  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 ) )  | 
						
						
							| 15 | 
							
								
							 | 
							fveqeq2 | 
							⊢ ( 𝑖  =  ∅  →  ( ( 𝑓 ‘ 𝑖 )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ↔  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) ) )  | 
						
						
							| 16 | 
							
								15
							 | 
							biimpar | 
							⊢ ( ( 𝑖  =  ∅  ∧  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  →  ( 𝑓 ‘ 𝑖 )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 17 | 
							
								16
							 | 
							adantr | 
							⊢ ( ( ( 𝑖  =  ∅  ∧  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 )  →  ( 𝑓 ‘ 𝑖 )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 18 | 
							
								
							 | 
							simpr | 
							⊢ ( ( ( 𝑖  =  ∅  ∧  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 )  →   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 )  | 
						
						
							| 19 | 
							
								17 18
							 | 
							eqsstrd | 
							⊢ ( ( ( 𝑖  =  ∅  ∧  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 )  →  ( 𝑓 ‘ 𝑖 )  ⊆  𝐵 )  | 
						
						
							| 20 | 
							
								19
							 | 
							3impa | 
							⊢ ( ( 𝑖  =  ∅  ∧  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ∧   pred ( 𝑋 ,  𝐴 ,  𝑅 )  ⊆  𝐵 )  →  ( 𝑓 ‘ 𝑖 )  ⊆  𝐵 )  | 
						
						
							| 21 | 
							
								14 20
							 | 
							syl | 
							⊢ ( ( 𝑖  =  ∅  ∧  ( ( 𝜃  ∧  𝜏  ∧  𝜒 )  ∧  𝜑0 ) )  →  ( 𝑓 ‘ 𝑖 )  ⊆  𝐵 )  |