| Step | Hyp | Ref | Expression | 
						
							| 1 |  | infpn2.1 | ⊢ 𝑆  =  { 𝑛  ∈  ℕ  ∣  ( 1  <  𝑛  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑛  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑛 ) ) ) } | 
						
							| 2 | 1 | ssrab3 | ⊢ 𝑆  ⊆  ℕ | 
						
							| 3 |  | infpn | ⊢ ( 𝑗  ∈  ℕ  →  ∃ 𝑘  ∈  ℕ ( 𝑗  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) | 
						
							| 4 |  | nnge1 | ⊢ ( 𝑗  ∈  ℕ  →  1  ≤  𝑗 ) | 
						
							| 5 | 4 | adantr | ⊢ ( ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ )  →  1  ≤  𝑗 ) | 
						
							| 6 |  | 1re | ⊢ 1  ∈  ℝ | 
						
							| 7 |  | nnre | ⊢ ( 𝑗  ∈  ℕ  →  𝑗  ∈  ℝ ) | 
						
							| 8 |  | nnre | ⊢ ( 𝑘  ∈  ℕ  →  𝑘  ∈  ℝ ) | 
						
							| 9 |  | lelttr | ⊢ ( ( 1  ∈  ℝ  ∧  𝑗  ∈  ℝ  ∧  𝑘  ∈  ℝ )  →  ( ( 1  ≤  𝑗  ∧  𝑗  <  𝑘 )  →  1  <  𝑘 ) ) | 
						
							| 10 | 6 7 8 9 | mp3an3an | ⊢ ( ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ )  →  ( ( 1  ≤  𝑗  ∧  𝑗  <  𝑘 )  →  1  <  𝑘 ) ) | 
						
							| 11 | 5 10 | mpand | ⊢ ( ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ )  →  ( 𝑗  <  𝑘  →  1  <  𝑘 ) ) | 
						
							| 12 | 11 | ancld | ⊢ ( ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ )  →  ( 𝑗  <  𝑘  →  ( 𝑗  <  𝑘  ∧  1  <  𝑘 ) ) ) | 
						
							| 13 | 12 | anim1d | ⊢ ( ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ )  →  ( ( 𝑗  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) )  →  ( ( 𝑗  <  𝑘  ∧  1  <  𝑘 )  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) | 
						
							| 14 |  | anass | ⊢ ( ( ( 𝑗  <  𝑘  ∧  1  <  𝑘 )  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) )  ↔  ( 𝑗  <  𝑘  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) | 
						
							| 15 | 13 14 | imbitrdi | ⊢ ( ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ )  →  ( ( 𝑗  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) )  →  ( 𝑗  <  𝑘  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) ) | 
						
							| 16 | 15 | reximdva | ⊢ ( 𝑗  ∈  ℕ  →  ( ∃ 𝑘  ∈  ℕ ( 𝑗  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) )  →  ∃ 𝑘  ∈  ℕ ( 𝑗  <  𝑘  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) ) | 
						
							| 17 | 3 16 | mpd | ⊢ ( 𝑗  ∈  ℕ  →  ∃ 𝑘  ∈  ℕ ( 𝑗  <  𝑘  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) | 
						
							| 18 |  | breq2 | ⊢ ( 𝑛  =  𝑘  →  ( 1  <  𝑛  ↔  1  <  𝑘 ) ) | 
						
							| 19 |  | oveq1 | ⊢ ( 𝑛  =  𝑘  →  ( 𝑛  /  𝑚 )  =  ( 𝑘  /  𝑚 ) ) | 
						
							| 20 | 19 | eleq1d | ⊢ ( 𝑛  =  𝑘  →  ( ( 𝑛  /  𝑚 )  ∈  ℕ  ↔  ( 𝑘  /  𝑚 )  ∈  ℕ ) ) | 
						
							| 21 |  | equequ2 | ⊢ ( 𝑛  =  𝑘  →  ( 𝑚  =  𝑛  ↔  𝑚  =  𝑘 ) ) | 
						
							| 22 | 21 | orbi2d | ⊢ ( 𝑛  =  𝑘  →  ( ( 𝑚  =  1  ∨  𝑚  =  𝑛 )  ↔  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) | 
						
							| 23 | 20 22 | imbi12d | ⊢ ( 𝑛  =  𝑘  →  ( ( ( 𝑛  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑛 ) )  ↔  ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) | 
						
							| 24 | 23 | ralbidv | ⊢ ( 𝑛  =  𝑘  →  ( ∀ 𝑚  ∈  ℕ ( ( 𝑛  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑛 ) )  ↔  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) | 
						
							| 25 | 18 24 | anbi12d | ⊢ ( 𝑛  =  𝑘  →  ( ( 1  <  𝑛  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑛  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑛 ) ) )  ↔  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) | 
						
							| 26 | 25 1 | elrab2 | ⊢ ( 𝑘  ∈  𝑆  ↔  ( 𝑘  ∈  ℕ  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) | 
						
							| 27 | 26 | anbi1i | ⊢ ( ( 𝑘  ∈  𝑆  ∧  𝑗  <  𝑘 )  ↔  ( ( 𝑘  ∈  ℕ  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) )  ∧  𝑗  <  𝑘 ) ) | 
						
							| 28 |  | anass | ⊢ ( ( ( 𝑘  ∈  ℕ  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) )  ∧  𝑗  <  𝑘 )  ↔  ( 𝑘  ∈  ℕ  ∧  ( ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) )  ∧  𝑗  <  𝑘 ) ) ) | 
						
							| 29 |  | ancom | ⊢ ( ( ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) )  ∧  𝑗  <  𝑘 )  ↔  ( 𝑗  <  𝑘  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) | 
						
							| 30 | 29 | anbi2i | ⊢ ( ( 𝑘  ∈  ℕ  ∧  ( ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) )  ∧  𝑗  <  𝑘 ) )  ↔  ( 𝑘  ∈  ℕ  ∧  ( 𝑗  <  𝑘  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) ) | 
						
							| 31 | 27 28 30 | 3bitri | ⊢ ( ( 𝑘  ∈  𝑆  ∧  𝑗  <  𝑘 )  ↔  ( 𝑘  ∈  ℕ  ∧  ( 𝑗  <  𝑘  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) ) | 
						
							| 32 | 31 | rexbii2 | ⊢ ( ∃ 𝑘  ∈  𝑆 𝑗  <  𝑘  ↔  ∃ 𝑘  ∈  ℕ ( 𝑗  <  𝑘  ∧  ( 1  <  𝑘  ∧  ∀ 𝑚  ∈  ℕ ( ( 𝑘  /  𝑚 )  ∈  ℕ  →  ( 𝑚  =  1  ∨  𝑚  =  𝑘 ) ) ) ) ) | 
						
							| 33 | 17 32 | sylibr | ⊢ ( 𝑗  ∈  ℕ  →  ∃ 𝑘  ∈  𝑆 𝑗  <  𝑘 ) | 
						
							| 34 | 33 | rgen | ⊢ ∀ 𝑗  ∈  ℕ ∃ 𝑘  ∈  𝑆 𝑗  <  𝑘 | 
						
							| 35 |  | unben | ⊢ ( ( 𝑆  ⊆  ℕ  ∧  ∀ 𝑗  ∈  ℕ ∃ 𝑘  ∈  𝑆 𝑗  <  𝑘 )  →  𝑆  ≈  ℕ ) | 
						
							| 36 | 2 34 35 | mp2an | ⊢ 𝑆  ≈  ℕ |