| Step | Hyp | Ref | Expression | 
						
							| 1 |  | unbenlem.1 | ⊢ 𝐺  =  ( rec ( ( 𝑥  ∈  V  ↦  ( 𝑥  +  1 ) ) ,  1 )  ↾  ω ) | 
						
							| 2 |  | nnex | ⊢ ℕ  ∈  V | 
						
							| 3 | 2 | ssex | ⊢ ( 𝐴  ⊆  ℕ  →  𝐴  ∈  V ) | 
						
							| 4 |  | 1z | ⊢ 1  ∈  ℤ | 
						
							| 5 | 4 1 | om2uzf1oi | ⊢ 𝐺 : ω –1-1-onto→ ( ℤ≥ ‘ 1 ) | 
						
							| 6 |  | nnuz | ⊢ ℕ  =  ( ℤ≥ ‘ 1 ) | 
						
							| 7 |  | f1oeq3 | ⊢ ( ℕ  =  ( ℤ≥ ‘ 1 )  →  ( 𝐺 : ω –1-1-onto→ ℕ  ↔  𝐺 : ω –1-1-onto→ ( ℤ≥ ‘ 1 ) ) ) | 
						
							| 8 | 6 7 | ax-mp | ⊢ ( 𝐺 : ω –1-1-onto→ ℕ  ↔  𝐺 : ω –1-1-onto→ ( ℤ≥ ‘ 1 ) ) | 
						
							| 9 | 5 8 | mpbir | ⊢ 𝐺 : ω –1-1-onto→ ℕ | 
						
							| 10 |  | f1ocnv | ⊢ ( 𝐺 : ω –1-1-onto→ ℕ  →  ◡ 𝐺 : ℕ –1-1-onto→ ω ) | 
						
							| 11 |  | f1of1 | ⊢ ( ◡ 𝐺 : ℕ –1-1-onto→ ω  →  ◡ 𝐺 : ℕ –1-1→ ω ) | 
						
							| 12 | 9 10 11 | mp2b | ⊢ ◡ 𝐺 : ℕ –1-1→ ω | 
						
							| 13 |  | f1ores | ⊢ ( ( ◡ 𝐺 : ℕ –1-1→ ω  ∧  𝐴  ⊆  ℕ )  →  ( ◡ 𝐺  ↾  𝐴 ) : 𝐴 –1-1-onto→ ( ◡ 𝐺  “  𝐴 ) ) | 
						
							| 14 | 12 13 | mpan | ⊢ ( 𝐴  ⊆  ℕ  →  ( ◡ 𝐺  ↾  𝐴 ) : 𝐴 –1-1-onto→ ( ◡ 𝐺  “  𝐴 ) ) | 
						
							| 15 |  | f1oeng | ⊢ ( ( 𝐴  ∈  V  ∧  ( ◡ 𝐺  ↾  𝐴 ) : 𝐴 –1-1-onto→ ( ◡ 𝐺  “  𝐴 ) )  →  𝐴  ≈  ( ◡ 𝐺  “  𝐴 ) ) | 
						
							| 16 | 3 14 15 | syl2anc | ⊢ ( 𝐴  ⊆  ℕ  →  𝐴  ≈  ( ◡ 𝐺  “  𝐴 ) ) | 
						
							| 17 | 16 | adantr | ⊢ ( ( 𝐴  ⊆  ℕ  ∧  ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛 )  →  𝐴  ≈  ( ◡ 𝐺  “  𝐴 ) ) | 
						
							| 18 |  | imassrn | ⊢ ( ◡ 𝐺  “  𝐴 )  ⊆  ran  ◡ 𝐺 | 
						
							| 19 |  | dfdm4 | ⊢ dom  𝐺  =  ran  ◡ 𝐺 | 
						
							| 20 |  | f1of | ⊢ ( 𝐺 : ω –1-1-onto→ ℕ  →  𝐺 : ω ⟶ ℕ ) | 
						
							| 21 | 9 20 | ax-mp | ⊢ 𝐺 : ω ⟶ ℕ | 
						
							| 22 | 21 | fdmi | ⊢ dom  𝐺  =  ω | 
						
							| 23 | 19 22 | eqtr3i | ⊢ ran  ◡ 𝐺  =  ω | 
						
							| 24 | 18 23 | sseqtri | ⊢ ( ◡ 𝐺  “  𝐴 )  ⊆  ω | 
						
							| 25 | 4 1 | om2uzuzi | ⊢ ( 𝑦  ∈  ω  →  ( 𝐺 ‘ 𝑦 )  ∈  ( ℤ≥ ‘ 1 ) ) | 
						
							| 26 | 25 6 | eleqtrrdi | ⊢ ( 𝑦  ∈  ω  →  ( 𝐺 ‘ 𝑦 )  ∈  ℕ ) | 
						
							| 27 |  | breq1 | ⊢ ( 𝑚  =  ( 𝐺 ‘ 𝑦 )  →  ( 𝑚  <  𝑛  ↔  ( 𝐺 ‘ 𝑦 )  <  𝑛 ) ) | 
						
							| 28 | 27 | rexbidv | ⊢ ( 𝑚  =  ( 𝐺 ‘ 𝑦 )  →  ( ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛  ↔  ∃ 𝑛  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  <  𝑛 ) ) | 
						
							| 29 | 28 | rspcv | ⊢ ( ( 𝐺 ‘ 𝑦 )  ∈  ℕ  →  ( ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛  →  ∃ 𝑛  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  <  𝑛 ) ) | 
						
							| 30 | 26 29 | syl | ⊢ ( 𝑦  ∈  ω  →  ( ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛  →  ∃ 𝑛  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  <  𝑛 ) ) | 
						
							| 31 | 30 | adantr | ⊢ ( ( 𝑦  ∈  ω  ∧  𝐴  ⊆  ℕ )  →  ( ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛  →  ∃ 𝑛  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  <  𝑛 ) ) | 
						
							| 32 |  | f1ocnv | ⊢ ( ( ◡ 𝐺  ↾  𝐴 ) : 𝐴 –1-1-onto→ ( ◡ 𝐺  “  𝐴 )  →  ◡ ( ◡ 𝐺  ↾  𝐴 ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴 ) | 
						
							| 33 | 14 32 | syl | ⊢ ( 𝐴  ⊆  ℕ  →  ◡ ( ◡ 𝐺  ↾  𝐴 ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴 ) | 
						
							| 34 |  | f1ofun | ⊢ ( 𝐺 : ω –1-1-onto→ ℕ  →  Fun  𝐺 ) | 
						
							| 35 | 9 34 | ax-mp | ⊢ Fun  𝐺 | 
						
							| 36 |  | funcnvres2 | ⊢ ( Fun  𝐺  →  ◡ ( ◡ 𝐺  ↾  𝐴 )  =  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ) | 
						
							| 37 |  | f1oeq1 | ⊢ ( ◡ ( ◡ 𝐺  ↾  𝐴 )  =  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) )  →  ( ◡ ( ◡ 𝐺  ↾  𝐴 ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴  ↔  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴 ) ) | 
						
							| 38 | 35 36 37 | mp2b | ⊢ ( ◡ ( ◡ 𝐺  ↾  𝐴 ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴  ↔  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴 ) | 
						
							| 39 | 33 38 | sylib | ⊢ ( 𝐴  ⊆  ℕ  →  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴 ) | 
						
							| 40 |  | f1ofo | ⊢ ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴  →  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –onto→ 𝐴 ) | 
						
							| 41 |  | forn | ⊢ ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –onto→ 𝐴  →  ran  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) )  =  𝐴 ) | 
						
							| 42 | 40 41 | syl | ⊢ ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴  →  ran  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) )  =  𝐴 ) | 
						
							| 43 | 42 | eleq2d | ⊢ ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴  →  ( 𝑛  ∈  ran  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) )  ↔  𝑛  ∈  𝐴 ) ) | 
						
							| 44 |  | f1ofn | ⊢ ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴  →  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) )  Fn  ( ◡ 𝐺  “  𝐴 ) ) | 
						
							| 45 |  | fvelrnb | ⊢ ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) )  Fn  ( ◡ 𝐺  “  𝐴 )  →  ( 𝑛  ∈  ran  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) )  ↔  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛 ) ) | 
						
							| 46 | 44 45 | syl | ⊢ ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴  →  ( 𝑛  ∈  ran  ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) )  ↔  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛 ) ) | 
						
							| 47 | 43 46 | bitr3d | ⊢ ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) : ( ◡ 𝐺  “  𝐴 ) –1-1-onto→ 𝐴  →  ( 𝑛  ∈  𝐴  ↔  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛 ) ) | 
						
							| 48 | 39 47 | syl | ⊢ ( 𝐴  ⊆  ℕ  →  ( 𝑛  ∈  𝐴  ↔  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛 ) ) | 
						
							| 49 | 48 | biimpa | ⊢ ( ( 𝐴  ⊆  ℕ  ∧  𝑛  ∈  𝐴 )  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛 ) | 
						
							| 50 |  | fvres | ⊢ ( 𝑚  ∈  ( ◡ 𝐺  “  𝐴 )  →  ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  ( 𝐺 ‘ 𝑚 ) ) | 
						
							| 51 | 50 | eqeq1d | ⊢ ( 𝑚  ∈  ( ◡ 𝐺  “  𝐴 )  →  ( ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛  ↔  ( 𝐺 ‘ 𝑚 )  =  𝑛 ) ) | 
						
							| 52 | 51 | biimpa | ⊢ ( ( 𝑚  ∈  ( ◡ 𝐺  “  𝐴 )  ∧  ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛 )  →  ( 𝐺 ‘ 𝑚 )  =  𝑛 ) | 
						
							| 53 | 52 | adantll | ⊢ ( ( ( 𝑦  ∈  ω  ∧  𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) )  ∧  ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛 )  →  ( 𝐺 ‘ 𝑚 )  =  𝑛 ) | 
						
							| 54 | 24 | sseli | ⊢ ( 𝑚  ∈  ( ◡ 𝐺  “  𝐴 )  →  𝑚  ∈  ω ) | 
						
							| 55 | 4 1 | om2uzlt2i | ⊢ ( ( 𝑦  ∈  ω  ∧  𝑚  ∈  ω )  →  ( 𝑦  ∈  𝑚  ↔  ( 𝐺 ‘ 𝑦 )  <  ( 𝐺 ‘ 𝑚 ) ) ) | 
						
							| 56 | 54 55 | sylan2 | ⊢ ( ( 𝑦  ∈  ω  ∧  𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) )  →  ( 𝑦  ∈  𝑚  ↔  ( 𝐺 ‘ 𝑦 )  <  ( 𝐺 ‘ 𝑚 ) ) ) | 
						
							| 57 |  | breq2 | ⊢ ( ( 𝐺 ‘ 𝑚 )  =  𝑛  →  ( ( 𝐺 ‘ 𝑦 )  <  ( 𝐺 ‘ 𝑚 )  ↔  ( 𝐺 ‘ 𝑦 )  <  𝑛 ) ) | 
						
							| 58 | 56 57 | sylan9bb | ⊢ ( ( ( 𝑦  ∈  ω  ∧  𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) )  ∧  ( 𝐺 ‘ 𝑚 )  =  𝑛 )  →  ( 𝑦  ∈  𝑚  ↔  ( 𝐺 ‘ 𝑦 )  <  𝑛 ) ) | 
						
							| 59 | 53 58 | syldan | ⊢ ( ( ( 𝑦  ∈  ω  ∧  𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) )  ∧  ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛 )  →  ( 𝑦  ∈  𝑚  ↔  ( 𝐺 ‘ 𝑦 )  <  𝑛 ) ) | 
						
							| 60 | 59 | biimparc | ⊢ ( ( ( 𝐺 ‘ 𝑦 )  <  𝑛  ∧  ( ( 𝑦  ∈  ω  ∧  𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) )  ∧  ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛 ) )  →  𝑦  ∈  𝑚 ) | 
						
							| 61 | 60 | exp44 | ⊢ ( ( 𝐺 ‘ 𝑦 )  <  𝑛  →  ( 𝑦  ∈  ω  →  ( 𝑚  ∈  ( ◡ 𝐺  “  𝐴 )  →  ( ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛  →  𝑦  ∈  𝑚 ) ) ) ) | 
						
							| 62 | 61 | imp31 | ⊢ ( ( ( ( 𝐺 ‘ 𝑦 )  <  𝑛  ∧  𝑦  ∈  ω )  ∧  𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) )  →  ( ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛  →  𝑦  ∈  𝑚 ) ) | 
						
							| 63 | 62 | reximdva | ⊢ ( ( ( 𝐺 ‘ 𝑦 )  <  𝑛  ∧  𝑦  ∈  ω )  →  ( ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) ( ( 𝐺  ↾  ( ◡ 𝐺  “  𝐴 ) ) ‘ 𝑚 )  =  𝑛  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) | 
						
							| 64 | 49 63 | syl5 | ⊢ ( ( ( 𝐺 ‘ 𝑦 )  <  𝑛  ∧  𝑦  ∈  ω )  →  ( ( 𝐴  ⊆  ℕ  ∧  𝑛  ∈  𝐴 )  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) | 
						
							| 65 | 64 | exp4b | ⊢ ( ( 𝐺 ‘ 𝑦 )  <  𝑛  →  ( 𝑦  ∈  ω  →  ( 𝐴  ⊆  ℕ  →  ( 𝑛  ∈  𝐴  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) ) ) | 
						
							| 66 | 65 | com4l | ⊢ ( 𝑦  ∈  ω  →  ( 𝐴  ⊆  ℕ  →  ( 𝑛  ∈  𝐴  →  ( ( 𝐺 ‘ 𝑦 )  <  𝑛  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) ) ) | 
						
							| 67 | 66 | imp | ⊢ ( ( 𝑦  ∈  ω  ∧  𝐴  ⊆  ℕ )  →  ( 𝑛  ∈  𝐴  →  ( ( 𝐺 ‘ 𝑦 )  <  𝑛  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) ) | 
						
							| 68 | 67 | rexlimdv | ⊢ ( ( 𝑦  ∈  ω  ∧  𝐴  ⊆  ℕ )  →  ( ∃ 𝑛  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  <  𝑛  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) | 
						
							| 69 | 31 68 | syld | ⊢ ( ( 𝑦  ∈  ω  ∧  𝐴  ⊆  ℕ )  →  ( ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) | 
						
							| 70 | 69 | ex | ⊢ ( 𝑦  ∈  ω  →  ( 𝐴  ⊆  ℕ  →  ( ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) ) | 
						
							| 71 | 70 | com3l | ⊢ ( 𝐴  ⊆  ℕ  →  ( ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛  →  ( 𝑦  ∈  ω  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) ) | 
						
							| 72 | 71 | imp | ⊢ ( ( 𝐴  ⊆  ℕ  ∧  ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛 )  →  ( 𝑦  ∈  ω  →  ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) ) | 
						
							| 73 | 72 | ralrimiv | ⊢ ( ( 𝐴  ⊆  ℕ  ∧  ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛 )  →  ∀ 𝑦  ∈  ω ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 ) | 
						
							| 74 |  | unbnn3 | ⊢ ( ( ( ◡ 𝐺  “  𝐴 )  ⊆  ω  ∧  ∀ 𝑦  ∈  ω ∃ 𝑚  ∈  ( ◡ 𝐺  “  𝐴 ) 𝑦  ∈  𝑚 )  →  ( ◡ 𝐺  “  𝐴 )  ≈  ω ) | 
						
							| 75 | 24 73 74 | sylancr | ⊢ ( ( 𝐴  ⊆  ℕ  ∧  ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛 )  →  ( ◡ 𝐺  “  𝐴 )  ≈  ω ) | 
						
							| 76 |  | entr | ⊢ ( ( 𝐴  ≈  ( ◡ 𝐺  “  𝐴 )  ∧  ( ◡ 𝐺  “  𝐴 )  ≈  ω )  →  𝐴  ≈  ω ) | 
						
							| 77 | 17 75 76 | syl2anc | ⊢ ( ( 𝐴  ⊆  ℕ  ∧  ∀ 𝑚  ∈  ℕ ∃ 𝑛  ∈  𝐴 𝑚  <  𝑛 )  →  𝐴  ≈  ω ) |