| Step | Hyp | Ref | Expression | 
						
							| 1 |  | elnnuz | ⊢ ( 𝑚  ∈  ℕ  ↔  𝑚  ∈  ( ℤ≥ ‘ 1 ) ) | 
						
							| 2 |  | uztrn | ⊢ ( ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  ∧  𝑚  ∈  ( ℤ≥ ‘ 1 ) )  →  𝑘  ∈  ( ℤ≥ ‘ 1 ) ) | 
						
							| 3 | 1 2 | sylan2b | ⊢ ( ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  ∧  𝑚  ∈  ℕ )  →  𝑘  ∈  ( ℤ≥ ‘ 1 ) ) | 
						
							| 4 |  | elnnuz | ⊢ ( 𝑘  ∈  ℕ  ↔  𝑘  ∈  ( ℤ≥ ‘ 1 ) ) | 
						
							| 5 | 3 4 | sylibr | ⊢ ( ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  ∧  𝑚  ∈  ℕ )  →  𝑘  ∈  ℕ ) | 
						
							| 6 | 5 | expcom | ⊢ ( 𝑚  ∈  ℕ  →  ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  →  𝑘  ∈  ℕ ) ) | 
						
							| 7 |  | eluzle | ⊢ ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  →  𝑚  ≤  𝑘 ) | 
						
							| 8 | 7 | a1i | ⊢ ( 𝑚  ∈  ℕ  →  ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  →  𝑚  ≤  𝑘 ) ) | 
						
							| 9 | 6 8 | jcad | ⊢ ( 𝑚  ∈  ℕ  →  ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  →  ( 𝑘  ∈  ℕ  ∧  𝑚  ≤  𝑘 ) ) ) | 
						
							| 10 |  | nnz | ⊢ ( 𝑘  ∈  ℕ  →  𝑘  ∈  ℤ ) | 
						
							| 11 |  | nnz | ⊢ ( 𝑚  ∈  ℕ  →  𝑚  ∈  ℤ ) | 
						
							| 12 |  | eluz2 | ⊢ ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  ↔  ( 𝑚  ∈  ℤ  ∧  𝑘  ∈  ℤ  ∧  𝑚  ≤  𝑘 ) ) | 
						
							| 13 | 12 | biimpri | ⊢ ( ( 𝑚  ∈  ℤ  ∧  𝑘  ∈  ℤ  ∧  𝑚  ≤  𝑘 )  →  𝑘  ∈  ( ℤ≥ ‘ 𝑚 ) ) | 
						
							| 14 | 11 13 | syl3an1 | ⊢ ( ( 𝑚  ∈  ℕ  ∧  𝑘  ∈  ℤ  ∧  𝑚  ≤  𝑘 )  →  𝑘  ∈  ( ℤ≥ ‘ 𝑚 ) ) | 
						
							| 15 | 10 14 | syl3an2 | ⊢ ( ( 𝑚  ∈  ℕ  ∧  𝑘  ∈  ℕ  ∧  𝑚  ≤  𝑘 )  →  𝑘  ∈  ( ℤ≥ ‘ 𝑚 ) ) | 
						
							| 16 | 15 | 3expib | ⊢ ( 𝑚  ∈  ℕ  →  ( ( 𝑘  ∈  ℕ  ∧  𝑚  ≤  𝑘 )  →  𝑘  ∈  ( ℤ≥ ‘ 𝑚 ) ) ) | 
						
							| 17 | 9 16 | impbid | ⊢ ( 𝑚  ∈  ℕ  →  ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  ↔  ( 𝑘  ∈  ℕ  ∧  𝑚  ≤  𝑘 ) ) ) | 
						
							| 18 | 17 | imbi1d | ⊢ ( 𝑚  ∈  ℕ  →  ( ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  →  𝜑 )  ↔  ( ( 𝑘  ∈  ℕ  ∧  𝑚  ≤  𝑘 )  →  𝜑 ) ) ) | 
						
							| 19 |  | impexp | ⊢ ( ( ( 𝑘  ∈  ℕ  ∧  𝑚  ≤  𝑘 )  →  𝜑 )  ↔  ( 𝑘  ∈  ℕ  →  ( 𝑚  ≤  𝑘  →  𝜑 ) ) ) | 
						
							| 20 | 18 19 | bitrdi | ⊢ ( 𝑚  ∈  ℕ  →  ( ( 𝑘  ∈  ( ℤ≥ ‘ 𝑚 )  →  𝜑 )  ↔  ( 𝑘  ∈  ℕ  →  ( 𝑚  ≤  𝑘  →  𝜑 ) ) ) ) |