| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eluz2b2 | ⊢ ( 𝑋  ∈  ( ℤ≥ ‘ 2 )  ↔  ( 𝑋  ∈  ℕ  ∧  1  <  𝑋 ) ) | 
						
							| 2 |  | 4z | ⊢ 4  ∈  ℤ | 
						
							| 3 | 2 | a1i | ⊢ ( ( ( 𝑋  ∈  ℕ  ∧  1  <  𝑋 )  ∧  𝑋  ∉  ℙ )  →  4  ∈  ℤ ) | 
						
							| 4 |  | nnz | ⊢ ( 𝑋  ∈  ℕ  →  𝑋  ∈  ℤ ) | 
						
							| 5 | 4 | ad2antrr | ⊢ ( ( ( 𝑋  ∈  ℕ  ∧  1  <  𝑋 )  ∧  𝑋  ∉  ℙ )  →  𝑋  ∈  ℤ ) | 
						
							| 6 |  | 1z | ⊢ 1  ∈  ℤ | 
						
							| 7 |  | zltp1le | ⊢ ( ( 1  ∈  ℤ  ∧  𝑋  ∈  ℤ )  →  ( 1  <  𝑋  ↔  ( 1  +  1 )  ≤  𝑋 ) ) | 
						
							| 8 | 6 4 7 | sylancr | ⊢ ( 𝑋  ∈  ℕ  →  ( 1  <  𝑋  ↔  ( 1  +  1 )  ≤  𝑋 ) ) | 
						
							| 9 |  | 1p1e2 | ⊢ ( 1  +  1 )  =  2 | 
						
							| 10 | 9 | breq1i | ⊢ ( ( 1  +  1 )  ≤  𝑋  ↔  2  ≤  𝑋 ) | 
						
							| 11 | 8 10 | bitrdi | ⊢ ( 𝑋  ∈  ℕ  →  ( 1  <  𝑋  ↔  2  ≤  𝑋 ) ) | 
						
							| 12 |  | 2re | ⊢ 2  ∈  ℝ | 
						
							| 13 |  | nnre | ⊢ ( 𝑋  ∈  ℕ  →  𝑋  ∈  ℝ ) | 
						
							| 14 |  | leloe | ⊢ ( ( 2  ∈  ℝ  ∧  𝑋  ∈  ℝ )  →  ( 2  ≤  𝑋  ↔  ( 2  <  𝑋  ∨  2  =  𝑋 ) ) ) | 
						
							| 15 | 12 13 14 | sylancr | ⊢ ( 𝑋  ∈  ℕ  →  ( 2  ≤  𝑋  ↔  ( 2  <  𝑋  ∨  2  =  𝑋 ) ) ) | 
						
							| 16 |  | 2z | ⊢ 2  ∈  ℤ | 
						
							| 17 |  | zltp1le | ⊢ ( ( 2  ∈  ℤ  ∧  𝑋  ∈  ℤ )  →  ( 2  <  𝑋  ↔  ( 2  +  1 )  ≤  𝑋 ) ) | 
						
							| 18 | 16 4 17 | sylancr | ⊢ ( 𝑋  ∈  ℕ  →  ( 2  <  𝑋  ↔  ( 2  +  1 )  ≤  𝑋 ) ) | 
						
							| 19 |  | 2p1e3 | ⊢ ( 2  +  1 )  =  3 | 
						
							| 20 | 19 | breq1i | ⊢ ( ( 2  +  1 )  ≤  𝑋  ↔  3  ≤  𝑋 ) | 
						
							| 21 | 18 20 | bitrdi | ⊢ ( 𝑋  ∈  ℕ  →  ( 2  <  𝑋  ↔  3  ≤  𝑋 ) ) | 
						
							| 22 |  | 3re | ⊢ 3  ∈  ℝ | 
						
							| 23 |  | leloe | ⊢ ( ( 3  ∈  ℝ  ∧  𝑋  ∈  ℝ )  →  ( 3  ≤  𝑋  ↔  ( 3  <  𝑋  ∨  3  =  𝑋 ) ) ) | 
						
							| 24 | 22 13 23 | sylancr | ⊢ ( 𝑋  ∈  ℕ  →  ( 3  ≤  𝑋  ↔  ( 3  <  𝑋  ∨  3  =  𝑋 ) ) ) | 
						
							| 25 |  | df-4 | ⊢ 4  =  ( 3  +  1 ) | 
						
							| 26 |  | 3z | ⊢ 3  ∈  ℤ | 
						
							| 27 |  | zltp1le | ⊢ ( ( 3  ∈  ℤ  ∧  𝑋  ∈  ℤ )  →  ( 3  <  𝑋  ↔  ( 3  +  1 )  ≤  𝑋 ) ) | 
						
							| 28 | 26 4 27 | sylancr | ⊢ ( 𝑋  ∈  ℕ  →  ( 3  <  𝑋  ↔  ( 3  +  1 )  ≤  𝑋 ) ) | 
						
							| 29 | 28 | biimpa | ⊢ ( ( 𝑋  ∈  ℕ  ∧  3  <  𝑋 )  →  ( 3  +  1 )  ≤  𝑋 ) | 
						
							| 30 | 25 29 | eqbrtrid | ⊢ ( ( 𝑋  ∈  ℕ  ∧  3  <  𝑋 )  →  4  ≤  𝑋 ) | 
						
							| 31 | 30 | a1d | ⊢ ( ( 𝑋  ∈  ℕ  ∧  3  <  𝑋 )  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) | 
						
							| 32 | 31 | ex | ⊢ ( 𝑋  ∈  ℕ  →  ( 3  <  𝑋  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) ) | 
						
							| 33 |  | neleq1 | ⊢ ( 𝑋  =  3  →  ( 𝑋  ∉  ℙ  ↔  3  ∉  ℙ ) ) | 
						
							| 34 | 33 | eqcoms | ⊢ ( 3  =  𝑋  →  ( 𝑋  ∉  ℙ  ↔  3  ∉  ℙ ) ) | 
						
							| 35 |  | 3prm | ⊢ 3  ∈  ℙ | 
						
							| 36 |  | pm2.24nel | ⊢ ( 3  ∈  ℙ  →  ( 3  ∉  ℙ  →  4  ≤  𝑋 ) ) | 
						
							| 37 | 35 36 | mp1i | ⊢ ( 3  =  𝑋  →  ( 3  ∉  ℙ  →  4  ≤  𝑋 ) ) | 
						
							| 38 | 34 37 | sylbid | ⊢ ( 3  =  𝑋  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) | 
						
							| 39 | 38 | a1i | ⊢ ( 𝑋  ∈  ℕ  →  ( 3  =  𝑋  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) ) | 
						
							| 40 | 32 39 | jaod | ⊢ ( 𝑋  ∈  ℕ  →  ( ( 3  <  𝑋  ∨  3  =  𝑋 )  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) ) | 
						
							| 41 | 24 40 | sylbid | ⊢ ( 𝑋  ∈  ℕ  →  ( 3  ≤  𝑋  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) ) | 
						
							| 42 | 21 41 | sylbid | ⊢ ( 𝑋  ∈  ℕ  →  ( 2  <  𝑋  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) ) | 
						
							| 43 |  | neleq1 | ⊢ ( 𝑋  =  2  →  ( 𝑋  ∉  ℙ  ↔  2  ∉  ℙ ) ) | 
						
							| 44 | 43 | eqcoms | ⊢ ( 2  =  𝑋  →  ( 𝑋  ∉  ℙ  ↔  2  ∉  ℙ ) ) | 
						
							| 45 |  | 2prm | ⊢ 2  ∈  ℙ | 
						
							| 46 |  | pm2.24nel | ⊢ ( 2  ∈  ℙ  →  ( 2  ∉  ℙ  →  4  ≤  𝑋 ) ) | 
						
							| 47 | 45 46 | mp1i | ⊢ ( 2  =  𝑋  →  ( 2  ∉  ℙ  →  4  ≤  𝑋 ) ) | 
						
							| 48 | 44 47 | sylbid | ⊢ ( 2  =  𝑋  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) | 
						
							| 49 | 48 | a1i | ⊢ ( 𝑋  ∈  ℕ  →  ( 2  =  𝑋  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) ) | 
						
							| 50 | 42 49 | jaod | ⊢ ( 𝑋  ∈  ℕ  →  ( ( 2  <  𝑋  ∨  2  =  𝑋 )  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) ) | 
						
							| 51 | 15 50 | sylbid | ⊢ ( 𝑋  ∈  ℕ  →  ( 2  ≤  𝑋  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) ) | 
						
							| 52 | 11 51 | sylbid | ⊢ ( 𝑋  ∈  ℕ  →  ( 1  <  𝑋  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) ) | 
						
							| 53 | 52 | imp | ⊢ ( ( 𝑋  ∈  ℕ  ∧  1  <  𝑋 )  →  ( 𝑋  ∉  ℙ  →  4  ≤  𝑋 ) ) | 
						
							| 54 | 53 | imp | ⊢ ( ( ( 𝑋  ∈  ℕ  ∧  1  <  𝑋 )  ∧  𝑋  ∉  ℙ )  →  4  ≤  𝑋 ) | 
						
							| 55 | 3 5 54 | 3jca | ⊢ ( ( ( 𝑋  ∈  ℕ  ∧  1  <  𝑋 )  ∧  𝑋  ∉  ℙ )  →  ( 4  ∈  ℤ  ∧  𝑋  ∈  ℤ  ∧  4  ≤  𝑋 ) ) | 
						
							| 56 | 55 | ex | ⊢ ( ( 𝑋  ∈  ℕ  ∧  1  <  𝑋 )  →  ( 𝑋  ∉  ℙ  →  ( 4  ∈  ℤ  ∧  𝑋  ∈  ℤ  ∧  4  ≤  𝑋 ) ) ) | 
						
							| 57 |  | eluz2 | ⊢ ( 𝑋  ∈  ( ℤ≥ ‘ 4 )  ↔  ( 4  ∈  ℤ  ∧  𝑋  ∈  ℤ  ∧  4  ≤  𝑋 ) ) | 
						
							| 58 | 56 57 | imbitrrdi | ⊢ ( ( 𝑋  ∈  ℕ  ∧  1  <  𝑋 )  →  ( 𝑋  ∉  ℙ  →  𝑋  ∈  ( ℤ≥ ‘ 4 ) ) ) | 
						
							| 59 | 1 58 | sylbi | ⊢ ( 𝑋  ∈  ( ℤ≥ ‘ 2 )  →  ( 𝑋  ∉  ℙ  →  𝑋  ∈  ( ℤ≥ ‘ 4 ) ) ) | 
						
							| 60 | 59 | imp | ⊢ ( ( 𝑋  ∈  ( ℤ≥ ‘ 2 )  ∧  𝑋  ∉  ℙ )  →  𝑋  ∈  ( ℤ≥ ‘ 4 ) ) |