| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mapfien.s | ⊢ 𝑆  =  { 𝑥  ∈  ( 𝐵  ↑m  𝐴 )  ∣  𝑥  finSupp  𝑍 } | 
						
							| 2 |  | mapfien.t | ⊢ 𝑇  =  { 𝑥  ∈  ( 𝐷  ↑m  𝐶 )  ∣  𝑥  finSupp  𝑊 } | 
						
							| 3 |  | mapfien.w | ⊢ 𝑊  =  ( 𝐺 ‘ 𝑍 ) | 
						
							| 4 |  | mapfien.f | ⊢ ( 𝜑  →  𝐹 : 𝐶 –1-1-onto→ 𝐴 ) | 
						
							| 5 |  | mapfien.g | ⊢ ( 𝜑  →  𝐺 : 𝐵 –1-1-onto→ 𝐷 ) | 
						
							| 6 |  | mapfien.a | ⊢ ( 𝜑  →  𝐴  ∈  𝑈 ) | 
						
							| 7 |  | mapfien.b | ⊢ ( 𝜑  →  𝐵  ∈  𝑉 ) | 
						
							| 8 |  | mapfien.c | ⊢ ( 𝜑  →  𝐶  ∈  𝑋 ) | 
						
							| 9 |  | mapfien.d | ⊢ ( 𝜑  →  𝐷  ∈  𝑌 ) | 
						
							| 10 |  | mapfien.z | ⊢ ( 𝜑  →  𝑍  ∈  𝐵 ) | 
						
							| 11 |  | f1ocnv | ⊢ ( 𝐺 : 𝐵 –1-1-onto→ 𝐷  →  ◡ 𝐺 : 𝐷 –1-1-onto→ 𝐵 ) | 
						
							| 12 |  | f1of | ⊢ ( ◡ 𝐺 : 𝐷 –1-1-onto→ 𝐵  →  ◡ 𝐺 : 𝐷 ⟶ 𝐵 ) | 
						
							| 13 | 5 11 12 | 3syl | ⊢ ( 𝜑  →  ◡ 𝐺 : 𝐷 ⟶ 𝐵 ) | 
						
							| 14 | 13 | adantr | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  ◡ 𝐺 : 𝐷 ⟶ 𝐵 ) | 
						
							| 15 |  | elrabi | ⊢ ( 𝑔  ∈  { 𝑥  ∈  ( 𝐷  ↑m  𝐶 )  ∣  𝑥  finSupp  𝑊 }  →  𝑔  ∈  ( 𝐷  ↑m  𝐶 ) ) | 
						
							| 16 | 15 2 | eleq2s | ⊢ ( 𝑔  ∈  𝑇  →  𝑔  ∈  ( 𝐷  ↑m  𝐶 ) ) | 
						
							| 17 | 16 | adantl | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  𝑔  ∈  ( 𝐷  ↑m  𝐶 ) ) | 
						
							| 18 |  | elmapi | ⊢ ( 𝑔  ∈  ( 𝐷  ↑m  𝐶 )  →  𝑔 : 𝐶 ⟶ 𝐷 ) | 
						
							| 19 | 17 18 | syl | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  𝑔 : 𝐶 ⟶ 𝐷 ) | 
						
							| 20 | 14 19 | fcod | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  ( ◡ 𝐺  ∘  𝑔 ) : 𝐶 ⟶ 𝐵 ) | 
						
							| 21 |  | f1ocnv | ⊢ ( 𝐹 : 𝐶 –1-1-onto→ 𝐴  →  ◡ 𝐹 : 𝐴 –1-1-onto→ 𝐶 ) | 
						
							| 22 |  | f1of | ⊢ ( ◡ 𝐹 : 𝐴 –1-1-onto→ 𝐶  →  ◡ 𝐹 : 𝐴 ⟶ 𝐶 ) | 
						
							| 23 | 4 21 22 | 3syl | ⊢ ( 𝜑  →  ◡ 𝐹 : 𝐴 ⟶ 𝐶 ) | 
						
							| 24 | 23 | adantr | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  ◡ 𝐹 : 𝐴 ⟶ 𝐶 ) | 
						
							| 25 | 20 24 | fcod | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 ) : 𝐴 ⟶ 𝐵 ) | 
						
							| 26 | 7 6 | elmapd | ⊢ ( 𝜑  →  ( ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  ∈  ( 𝐵  ↑m  𝐴 )  ↔  ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 ) : 𝐴 ⟶ 𝐵 ) ) | 
						
							| 27 | 26 | adantr | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  ( ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  ∈  ( 𝐵  ↑m  𝐴 )  ↔  ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 ) : 𝐴 ⟶ 𝐵 ) ) | 
						
							| 28 | 25 27 | mpbird | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  ∈  ( 𝐵  ↑m  𝐴 ) ) | 
						
							| 29 | 1 2 3 4 5 6 7 8 9 10 | mapfienlem2 | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  finSupp  𝑍 ) | 
						
							| 30 |  | breq1 | ⊢ ( 𝑥  =  ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  →  ( 𝑥  finSupp  𝑍  ↔  ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  finSupp  𝑍 ) ) | 
						
							| 31 | 30 1 | elrab2 | ⊢ ( ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  ∈  𝑆  ↔  ( ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  ∈  ( 𝐵  ↑m  𝐴 )  ∧  ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  finSupp  𝑍 ) ) | 
						
							| 32 | 28 29 31 | sylanbrc | ⊢ ( ( 𝜑  ∧  𝑔  ∈  𝑇 )  →  ( ( ◡ 𝐺  ∘  𝑔 )  ∘  ◡ 𝐹 )  ∈  𝑆 ) |