| Step | Hyp | Ref | Expression | 
						
							| 1 |  | psrgrp.s | ⊢ 𝑆  =  ( 𝐼  mPwSer  𝑅 ) | 
						
							| 2 |  | psrgrp.i | ⊢ ( 𝜑  →  𝐼  ∈  𝑉 ) | 
						
							| 3 |  | psrgrp.r | ⊢ ( 𝜑  →  𝑅  ∈  Grp ) | 
						
							| 4 |  | psrnegcl.d | ⊢ 𝐷  =  { 𝑓  ∈  ( ℕ0  ↑m  𝐼 )  ∣  ( ◡ 𝑓  “  ℕ )  ∈  Fin } | 
						
							| 5 |  | psrnegcl.i | ⊢ 𝑁  =  ( invg ‘ 𝑅 ) | 
						
							| 6 |  | psrnegcl.b | ⊢ 𝐵  =  ( Base ‘ 𝑆 ) | 
						
							| 7 |  | psrnegcl.z | ⊢ ( 𝜑  →  𝑋  ∈  𝐵 ) | 
						
							| 8 |  | eqid | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑅 ) | 
						
							| 9 | 8 5 3 | grpinvf1o | ⊢ ( 𝜑  →  𝑁 : ( Base ‘ 𝑅 ) –1-1-onto→ ( Base ‘ 𝑅 ) ) | 
						
							| 10 |  | f1of | ⊢ ( 𝑁 : ( Base ‘ 𝑅 ) –1-1-onto→ ( Base ‘ 𝑅 )  →  𝑁 : ( Base ‘ 𝑅 ) ⟶ ( Base ‘ 𝑅 ) ) | 
						
							| 11 | 9 10 | syl | ⊢ ( 𝜑  →  𝑁 : ( Base ‘ 𝑅 ) ⟶ ( Base ‘ 𝑅 ) ) | 
						
							| 12 | 1 8 4 6 7 | psrelbas | ⊢ ( 𝜑  →  𝑋 : 𝐷 ⟶ ( Base ‘ 𝑅 ) ) | 
						
							| 13 |  | fco | ⊢ ( ( 𝑁 : ( Base ‘ 𝑅 ) ⟶ ( Base ‘ 𝑅 )  ∧  𝑋 : 𝐷 ⟶ ( Base ‘ 𝑅 ) )  →  ( 𝑁  ∘  𝑋 ) : 𝐷 ⟶ ( Base ‘ 𝑅 ) ) | 
						
							| 14 | 11 12 13 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁  ∘  𝑋 ) : 𝐷 ⟶ ( Base ‘ 𝑅 ) ) | 
						
							| 15 |  | fvex | ⊢ ( Base ‘ 𝑅 )  ∈  V | 
						
							| 16 |  | ovex | ⊢ ( ℕ0  ↑m  𝐼 )  ∈  V | 
						
							| 17 | 4 16 | rabex2 | ⊢ 𝐷  ∈  V | 
						
							| 18 | 15 17 | elmap | ⊢ ( ( 𝑁  ∘  𝑋 )  ∈  ( ( Base ‘ 𝑅 )  ↑m  𝐷 )  ↔  ( 𝑁  ∘  𝑋 ) : 𝐷 ⟶ ( Base ‘ 𝑅 ) ) | 
						
							| 19 | 14 18 | sylibr | ⊢ ( 𝜑  →  ( 𝑁  ∘  𝑋 )  ∈  ( ( Base ‘ 𝑅 )  ↑m  𝐷 ) ) | 
						
							| 20 | 1 8 4 6 2 | psrbas | ⊢ ( 𝜑  →  𝐵  =  ( ( Base ‘ 𝑅 )  ↑m  𝐷 ) ) | 
						
							| 21 | 19 20 | eleqtrrd | ⊢ ( 𝜑  →  ( 𝑁  ∘  𝑋 )  ∈  𝐵 ) |