| Step | Hyp | Ref | Expression | 
						
							| 1 |  | coe1fval.a | ⊢ 𝐴  =  ( coe1 ‘ 𝐹 ) | 
						
							| 2 |  | coe1f2.b | ⊢ 𝐵  =  ( Base ‘ 𝑃 ) | 
						
							| 3 |  | coe1f2.p | ⊢ 𝑃  =  ( PwSer1 ‘ 𝑅 ) | 
						
							| 4 |  | coe1f2.k | ⊢ 𝐾  =  ( Base ‘ 𝑅 ) | 
						
							| 5 | 3 2 4 | psr1basf | ⊢ ( 𝐹  ∈  𝐵  →  𝐹 : ( ℕ0  ↑m  1o ) ⟶ 𝐾 ) | 
						
							| 6 |  | df1o2 | ⊢ 1o  =  { ∅ } | 
						
							| 7 |  | nn0ex | ⊢ ℕ0  ∈  V | 
						
							| 8 |  | 0ex | ⊢ ∅  ∈  V | 
						
							| 9 |  | eqid | ⊢ ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) )  =  ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) | 
						
							| 10 | 6 7 8 9 | mapsnf1o3 | ⊢ ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) : ℕ0 –1-1-onto→ ( ℕ0  ↑m  1o ) | 
						
							| 11 |  | f1of | ⊢ ( ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) : ℕ0 –1-1-onto→ ( ℕ0  ↑m  1o )  →  ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) : ℕ0 ⟶ ( ℕ0  ↑m  1o ) ) | 
						
							| 12 | 10 11 | ax-mp | ⊢ ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) : ℕ0 ⟶ ( ℕ0  ↑m  1o ) | 
						
							| 13 |  | fco | ⊢ ( ( 𝐹 : ( ℕ0  ↑m  1o ) ⟶ 𝐾  ∧  ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) : ℕ0 ⟶ ( ℕ0  ↑m  1o ) )  →  ( 𝐹  ∘  ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) ) : ℕ0 ⟶ 𝐾 ) | 
						
							| 14 | 5 12 13 | sylancl | ⊢ ( 𝐹  ∈  𝐵  →  ( 𝐹  ∘  ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) ) : ℕ0 ⟶ 𝐾 ) | 
						
							| 15 | 1 2 3 9 | coe1fval3 | ⊢ ( 𝐹  ∈  𝐵  →  𝐴  =  ( 𝐹  ∘  ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) ) ) | 
						
							| 16 | 15 | feq1d | ⊢ ( 𝐹  ∈  𝐵  →  ( 𝐴 : ℕ0 ⟶ 𝐾  ↔  ( 𝐹  ∘  ( 𝑥  ∈  ℕ0  ↦  ( 1o  ×  { 𝑥 } ) ) ) : ℕ0 ⟶ 𝐾 ) ) | 
						
							| 17 | 14 16 | mpbird | ⊢ ( 𝐹  ∈  𝐵  →  𝐴 : ℕ0 ⟶ 𝐾 ) |