| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ntrnei.o | ⊢ 𝑂  =  ( 𝑖  ∈  V ,  𝑗  ∈  V  ↦  ( 𝑘  ∈  ( 𝒫  𝑗  ↑m  𝑖 )  ↦  ( 𝑙  ∈  𝑗  ↦  { 𝑚  ∈  𝑖  ∣  𝑙  ∈  ( 𝑘 ‘ 𝑚 ) } ) ) ) | 
						
							| 2 |  | ntrnei.f | ⊢ 𝐹  =  ( 𝒫  𝐵 𝑂 𝐵 ) | 
						
							| 3 |  | ntrnei.r | ⊢ ( 𝜑  →  𝐼 𝐹 𝑁 ) | 
						
							| 4 | 1 2 3 | ntrneif1o | ⊢ ( 𝜑  →  𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) ) | 
						
							| 5 | 1 2 3 | ntrneinex | ⊢ ( 𝜑  →  𝑁  ∈  ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) ) | 
						
							| 6 |  | dff1o3 | ⊢ ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  ↔  ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  ∧  Fun  ◡ 𝐹 ) ) | 
						
							| 7 | 6 | simprbi | ⊢ ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  →  Fun  ◡ 𝐹 ) | 
						
							| 8 | 7 | adantr | ⊢ ( ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  ∧  𝑁  ∈  ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) )  →  Fun  ◡ 𝐹 ) | 
						
							| 9 |  | df-rn | ⊢ ran  𝐹  =  dom  ◡ 𝐹 | 
						
							| 10 |  | f1ofo | ⊢ ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  →  𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) ) | 
						
							| 11 |  | forn | ⊢ ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  →  ran  𝐹  =  ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) ) | 
						
							| 12 | 10 11 | syl | ⊢ ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  →  ran  𝐹  =  ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) ) | 
						
							| 13 | 9 12 | eqtr3id | ⊢ ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  →  dom  ◡ 𝐹  =  ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) ) | 
						
							| 14 | 13 | eleq2d | ⊢ ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  →  ( 𝑁  ∈  dom  ◡ 𝐹  ↔  𝑁  ∈  ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) ) ) | 
						
							| 15 | 14 | biimpar | ⊢ ( ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  ∧  𝑁  ∈  ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) )  →  𝑁  ∈  dom  ◡ 𝐹 ) | 
						
							| 16 | 8 15 | jca | ⊢ ( ( 𝐹 : ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) –1-1-onto→ ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  ∧  𝑁  ∈  ( 𝒫  𝒫  𝐵  ↑m  𝐵 ) )  →  ( Fun  ◡ 𝐹  ∧  𝑁  ∈  dom  ◡ 𝐹 ) ) | 
						
							| 17 | 4 5 16 | syl2anc | ⊢ ( 𝜑  →  ( Fun  ◡ 𝐹  ∧  𝑁  ∈  dom  ◡ 𝐹 ) ) | 
						
							| 18 |  | funbrfvb | ⊢ ( ( Fun  ◡ 𝐹  ∧  𝑁  ∈  dom  ◡ 𝐹 )  →  ( ( ◡ 𝐹 ‘ 𝑁 )  =  𝐼  ↔  𝑁 ◡ 𝐹 𝐼 ) ) | 
						
							| 19 | 17 18 | syl | ⊢ ( 𝜑  →  ( ( ◡ 𝐹 ‘ 𝑁 )  =  𝐼  ↔  𝑁 ◡ 𝐹 𝐼 ) ) | 
						
							| 20 | 1 2 3 | ntrneiiex | ⊢ ( 𝜑  →  𝐼  ∈  ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) ) | 
						
							| 21 |  | brcnvg | ⊢ ( ( 𝑁  ∈  ( 𝒫  𝒫  𝐵  ↑m  𝐵 )  ∧  𝐼  ∈  ( 𝒫  𝐵  ↑m  𝒫  𝐵 ) )  →  ( 𝑁 ◡ 𝐹 𝐼  ↔  𝐼 𝐹 𝑁 ) ) | 
						
							| 22 | 5 20 21 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁 ◡ 𝐹 𝐼  ↔  𝐼 𝐹 𝑁 ) ) | 
						
							| 23 | 19 22 | bitrd | ⊢ ( 𝜑  →  ( ( ◡ 𝐹 ‘ 𝑁 )  =  𝐼  ↔  𝐼 𝐹 𝑁 ) ) | 
						
							| 24 | 3 23 | mpbird | ⊢ ( 𝜑  →  ( ◡ 𝐹 ‘ 𝑁 )  =  𝐼 ) |