| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eleei | ⊢ ( 𝐴  ∈  ( 𝔼 ‘ 𝑁 )  →  𝐴 : ( 1 ... 𝑁 ) ⟶ ℝ ) | 
						
							| 2 |  | eleei | ⊢ ( 𝐴  ∈  ( 𝔼 ‘ 𝑀 )  →  𝐴 : ( 1 ... 𝑀 ) ⟶ ℝ ) | 
						
							| 3 |  | fdm | ⊢ ( 𝐴 : ( 1 ... 𝑁 ) ⟶ ℝ  →  dom  𝐴  =  ( 1 ... 𝑁 ) ) | 
						
							| 4 |  | fdm | ⊢ ( 𝐴 : ( 1 ... 𝑀 ) ⟶ ℝ  →  dom  𝐴  =  ( 1 ... 𝑀 ) ) | 
						
							| 5 | 3 4 | sylan9req | ⊢ ( ( 𝐴 : ( 1 ... 𝑁 ) ⟶ ℝ  ∧  𝐴 : ( 1 ... 𝑀 ) ⟶ ℝ )  →  ( 1 ... 𝑁 )  =  ( 1 ... 𝑀 ) ) | 
						
							| 6 | 1 2 5 | syl2an | ⊢ ( ( 𝐴  ∈  ( 𝔼 ‘ 𝑁 )  ∧  𝐴  ∈  ( 𝔼 ‘ 𝑀 ) )  →  ( 1 ... 𝑁 )  =  ( 1 ... 𝑀 ) ) | 
						
							| 7 |  | eleenn | ⊢ ( 𝐴  ∈  ( 𝔼 ‘ 𝑁 )  →  𝑁  ∈  ℕ ) | 
						
							| 8 |  | nnuz | ⊢ ℕ  =  ( ℤ≥ ‘ 1 ) | 
						
							| 9 | 7 8 | eleqtrdi | ⊢ ( 𝐴  ∈  ( 𝔼 ‘ 𝑁 )  →  𝑁  ∈  ( ℤ≥ ‘ 1 ) ) | 
						
							| 10 | 9 | adantr | ⊢ ( ( 𝐴  ∈  ( 𝔼 ‘ 𝑁 )  ∧  𝐴  ∈  ( 𝔼 ‘ 𝑀 ) )  →  𝑁  ∈  ( ℤ≥ ‘ 1 ) ) | 
						
							| 11 |  | fzopth | ⊢ ( 𝑁  ∈  ( ℤ≥ ‘ 1 )  →  ( ( 1 ... 𝑁 )  =  ( 1 ... 𝑀 )  ↔  ( 1  =  1  ∧  𝑁  =  𝑀 ) ) ) | 
						
							| 12 | 10 11 | syl | ⊢ ( ( 𝐴  ∈  ( 𝔼 ‘ 𝑁 )  ∧  𝐴  ∈  ( 𝔼 ‘ 𝑀 ) )  →  ( ( 1 ... 𝑁 )  =  ( 1 ... 𝑀 )  ↔  ( 1  =  1  ∧  𝑁  =  𝑀 ) ) ) | 
						
							| 13 | 6 12 | mpbid | ⊢ ( ( 𝐴  ∈  ( 𝔼 ‘ 𝑁 )  ∧  𝐴  ∈  ( 𝔼 ‘ 𝑀 ) )  →  ( 1  =  1  ∧  𝑁  =  𝑀 ) ) | 
						
							| 14 | 13 | simprd | ⊢ ( ( 𝐴  ∈  ( 𝔼 ‘ 𝑁 )  ∧  𝐴  ∈  ( 𝔼 ‘ 𝑀 ) )  →  𝑁  =  𝑀 ) |