| Step | Hyp | Ref | Expression | 
						
							| 1 |  | rngcsectALTV.c | ⊢ 𝐶  =  ( RngCatALTV ‘ 𝑈 ) | 
						
							| 2 |  | rngcsectALTV.b | ⊢ 𝐵  =  ( Base ‘ 𝐶 ) | 
						
							| 3 |  | rngcsectALTV.u | ⊢ ( 𝜑  →  𝑈  ∈  𝑉 ) | 
						
							| 4 |  | rngcsectALTV.x | ⊢ ( 𝜑  →  𝑋  ∈  𝐵 ) | 
						
							| 5 |  | rngcsectALTV.y | ⊢ ( 𝜑  →  𝑌  ∈  𝐵 ) | 
						
							| 6 |  | rngcisoALTV.n | ⊢ 𝐼  =  ( Iso ‘ 𝐶 ) | 
						
							| 7 |  | eqid | ⊢ ( Inv ‘ 𝐶 )  =  ( Inv ‘ 𝐶 ) | 
						
							| 8 | 1 | rngccatALTV | ⊢ ( 𝑈  ∈  𝑉  →  𝐶  ∈  Cat ) | 
						
							| 9 | 3 8 | syl | ⊢ ( 𝜑  →  𝐶  ∈  Cat ) | 
						
							| 10 | 2 7 9 4 5 6 | isoval | ⊢ ( 𝜑  →  ( 𝑋 𝐼 𝑌 )  =  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) | 
						
							| 11 | 10 | eleq2d | ⊢ ( 𝜑  →  ( 𝐹  ∈  ( 𝑋 𝐼 𝑌 )  ↔  𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) ) | 
						
							| 12 | 2 7 9 4 5 | invfun | ⊢ ( 𝜑  →  Fun  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) | 
						
							| 13 |  | funfvbrb | ⊢ ( Fun  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 )  →  ( 𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 )  ↔  𝐹 ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ( ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ‘ 𝐹 ) ) ) | 
						
							| 14 | 12 13 | syl | ⊢ ( 𝜑  →  ( 𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 )  ↔  𝐹 ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ( ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ‘ 𝐹 ) ) ) | 
						
							| 15 | 1 2 3 4 5 7 | rngcinvALTV | ⊢ ( 𝜑  →  ( 𝐹 ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ( ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ‘ 𝐹 )  ↔  ( 𝐹  ∈  ( 𝑋  RngIso  𝑌 )  ∧  ( ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ‘ 𝐹 )  =  ◡ 𝐹 ) ) ) | 
						
							| 16 |  | simpl | ⊢ ( ( 𝐹  ∈  ( 𝑋  RngIso  𝑌 )  ∧  ( ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ‘ 𝐹 )  =  ◡ 𝐹 )  →  𝐹  ∈  ( 𝑋  RngIso  𝑌 ) ) | 
						
							| 17 | 15 16 | biimtrdi | ⊢ ( 𝜑  →  ( 𝐹 ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ( ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ‘ 𝐹 )  →  𝐹  ∈  ( 𝑋  RngIso  𝑌 ) ) ) | 
						
							| 18 | 14 17 | sylbid | ⊢ ( 𝜑  →  ( 𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 )  →  𝐹  ∈  ( 𝑋  RngIso  𝑌 ) ) ) | 
						
							| 19 |  | eqid | ⊢ ◡ 𝐹  =  ◡ 𝐹 | 
						
							| 20 | 1 2 3 4 5 7 | rngcinvALTV | ⊢ ( 𝜑  →  ( 𝐹 ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ◡ 𝐹  ↔  ( 𝐹  ∈  ( 𝑋  RngIso  𝑌 )  ∧  ◡ 𝐹  =  ◡ 𝐹 ) ) ) | 
						
							| 21 |  | funrel | ⊢ ( Fun  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 )  →  Rel  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) | 
						
							| 22 | 12 21 | syl | ⊢ ( 𝜑  →  Rel  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) | 
						
							| 23 |  | releldm | ⊢ ( ( Rel  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 )  ∧  𝐹 ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ◡ 𝐹 )  →  𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) | 
						
							| 24 | 23 | ex | ⊢ ( Rel  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 )  →  ( 𝐹 ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ◡ 𝐹  →  𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) ) | 
						
							| 25 | 22 24 | syl | ⊢ ( 𝜑  →  ( 𝐹 ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ◡ 𝐹  →  𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) ) | 
						
							| 26 | 20 25 | sylbird | ⊢ ( 𝜑  →  ( ( 𝐹  ∈  ( 𝑋  RngIso  𝑌 )  ∧  ◡ 𝐹  =  ◡ 𝐹 )  →  𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) ) | 
						
							| 27 | 19 26 | mpan2i | ⊢ ( 𝜑  →  ( 𝐹  ∈  ( 𝑋  RngIso  𝑌 )  →  𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 ) ) ) | 
						
							| 28 | 18 27 | impbid | ⊢ ( 𝜑  →  ( 𝐹  ∈  dom  ( 𝑋 ( Inv ‘ 𝐶 ) 𝑌 )  ↔  𝐹  ∈  ( 𝑋  RngIso  𝑌 ) ) ) | 
						
							| 29 | 11 28 | bitrd | ⊢ ( 𝜑  →  ( 𝐹  ∈  ( 𝑋 𝐼 𝑌 )  ↔  𝐹  ∈  ( 𝑋  RngIso  𝑌 ) ) ) |