| Step | Hyp | Ref | Expression | 
						
							| 1 |  | seqomlem.a | ⊢ 𝑄  =  rec ( ( 𝑖  ∈  ω ,  𝑣  ∈  V  ↦  〈 suc  𝑖 ,  ( 𝑖 𝐹 𝑣 ) 〉 ) ,  〈 ∅ ,  (  I  ‘ 𝐼 ) 〉 ) | 
						
							| 2 |  | peano1 | ⊢ ∅  ∈  ω | 
						
							| 3 |  | fvres | ⊢ ( ∅  ∈  ω  →  ( ( 𝑄  ↾  ω ) ‘ ∅ )  =  ( 𝑄 ‘ ∅ ) ) | 
						
							| 4 | 2 3 | ax-mp | ⊢ ( ( 𝑄  ↾  ω ) ‘ ∅ )  =  ( 𝑄 ‘ ∅ ) | 
						
							| 5 | 1 | fveq1i | ⊢ ( 𝑄 ‘ ∅ )  =  ( rec ( ( 𝑖  ∈  ω ,  𝑣  ∈  V  ↦  〈 suc  𝑖 ,  ( 𝑖 𝐹 𝑣 ) 〉 ) ,  〈 ∅ ,  (  I  ‘ 𝐼 ) 〉 ) ‘ ∅ ) | 
						
							| 6 |  | opex | ⊢ 〈 ∅ ,  (  I  ‘ 𝐼 ) 〉  ∈  V | 
						
							| 7 | 6 | rdg0 | ⊢ ( rec ( ( 𝑖  ∈  ω ,  𝑣  ∈  V  ↦  〈 suc  𝑖 ,  ( 𝑖 𝐹 𝑣 ) 〉 ) ,  〈 ∅ ,  (  I  ‘ 𝐼 ) 〉 ) ‘ ∅ )  =  〈 ∅ ,  (  I  ‘ 𝐼 ) 〉 | 
						
							| 8 | 4 5 7 | 3eqtri | ⊢ ( ( 𝑄  ↾  ω ) ‘ ∅ )  =  〈 ∅ ,  (  I  ‘ 𝐼 ) 〉 | 
						
							| 9 |  | frfnom | ⊢ ( rec ( ( 𝑖  ∈  ω ,  𝑣  ∈  V  ↦  〈 suc  𝑖 ,  ( 𝑖 𝐹 𝑣 ) 〉 ) ,  〈 ∅ ,  (  I  ‘ 𝐼 ) 〉 )  ↾  ω )  Fn  ω | 
						
							| 10 | 1 | reseq1i | ⊢ ( 𝑄  ↾  ω )  =  ( rec ( ( 𝑖  ∈  ω ,  𝑣  ∈  V  ↦  〈 suc  𝑖 ,  ( 𝑖 𝐹 𝑣 ) 〉 ) ,  〈 ∅ ,  (  I  ‘ 𝐼 ) 〉 )  ↾  ω ) | 
						
							| 11 | 10 | fneq1i | ⊢ ( ( 𝑄  ↾  ω )  Fn  ω  ↔  ( rec ( ( 𝑖  ∈  ω ,  𝑣  ∈  V  ↦  〈 suc  𝑖 ,  ( 𝑖 𝐹 𝑣 ) 〉 ) ,  〈 ∅ ,  (  I  ‘ 𝐼 ) 〉 )  ↾  ω )  Fn  ω ) | 
						
							| 12 | 9 11 | mpbir | ⊢ ( 𝑄  ↾  ω )  Fn  ω | 
						
							| 13 |  | fnfvelrn | ⊢ ( ( ( 𝑄  ↾  ω )  Fn  ω  ∧  ∅  ∈  ω )  →  ( ( 𝑄  ↾  ω ) ‘ ∅ )  ∈  ran  ( 𝑄  ↾  ω ) ) | 
						
							| 14 | 12 2 13 | mp2an | ⊢ ( ( 𝑄  ↾  ω ) ‘ ∅ )  ∈  ran  ( 𝑄  ↾  ω ) | 
						
							| 15 | 8 14 | eqeltrri | ⊢ 〈 ∅ ,  (  I  ‘ 𝐼 ) 〉  ∈  ran  ( 𝑄  ↾  ω ) | 
						
							| 16 |  | df-ima | ⊢ ( 𝑄  “  ω )  =  ran  ( 𝑄  ↾  ω ) | 
						
							| 17 | 15 16 | eleqtrri | ⊢ 〈 ∅ ,  (  I  ‘ 𝐼 ) 〉  ∈  ( 𝑄  “  ω ) | 
						
							| 18 |  | df-br | ⊢ ( ∅ ( 𝑄  “  ω ) (  I  ‘ 𝐼 )  ↔  〈 ∅ ,  (  I  ‘ 𝐼 ) 〉  ∈  ( 𝑄  “  ω ) ) | 
						
							| 19 | 17 18 | mpbir | ⊢ ∅ ( 𝑄  “  ω ) (  I  ‘ 𝐼 ) | 
						
							| 20 | 1 | seqomlem2 | ⊢ ( 𝑄  “  ω )  Fn  ω | 
						
							| 21 |  | fnbrfvb | ⊢ ( ( ( 𝑄  “  ω )  Fn  ω  ∧  ∅  ∈  ω )  →  ( ( ( 𝑄  “  ω ) ‘ ∅ )  =  (  I  ‘ 𝐼 )  ↔  ∅ ( 𝑄  “  ω ) (  I  ‘ 𝐼 ) ) ) | 
						
							| 22 | 20 2 21 | mp2an | ⊢ ( ( ( 𝑄  “  ω ) ‘ ∅ )  =  (  I  ‘ 𝐼 )  ↔  ∅ ( 𝑄  “  ω ) (  I  ‘ 𝐼 ) ) | 
						
							| 23 | 19 22 | mpbir | ⊢ ( ( 𝑄  “  ω ) ‘ ∅ )  =  (  I  ‘ 𝐼 ) |