| Step | Hyp | Ref | Expression | 
						
							| 1 |  | biid | ⊢ ( ( 𝑎  <  𝑏  ∧  ( ( 𝑎 ↑ 2 )  +  ( 𝑏 ↑ 2 ) )  =  𝑃 )  ↔  ( 𝑎  <  𝑏  ∧  ( ( 𝑎 ↑ 2 )  +  ( 𝑏 ↑ 2 ) )  =  𝑃 ) ) | 
						
							| 2 | 1 | 2sqreult | ⊢ ( ( 𝑃  ∈  ℙ  ∧  ( 𝑃  mod  4 )  =  1 )  →  ( ∃! 𝑎  ∈  ℕ0 ∃ 𝑏  ∈  ℕ0 ( 𝑎  <  𝑏  ∧  ( ( 𝑎 ↑ 2 )  +  ( 𝑏 ↑ 2 ) )  =  𝑃 )  ∧  ∃! 𝑏  ∈  ℕ0 ∃ 𝑎  ∈  ℕ0 ( 𝑎  <  𝑏  ∧  ( ( 𝑎 ↑ 2 )  +  ( 𝑏 ↑ 2 ) )  =  𝑃 ) ) ) | 
						
							| 3 |  | fveq2 | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( 1st  ‘ 𝑝 )  =  ( 1st  ‘ 〈 𝑎 ,  𝑏 〉 ) ) | 
						
							| 4 |  | fveq2 | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( 2nd  ‘ 𝑝 )  =  ( 2nd  ‘ 〈 𝑎 ,  𝑏 〉 ) ) | 
						
							| 5 | 3 4 | breq12d | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( ( 1st  ‘ 𝑝 )  <  ( 2nd  ‘ 𝑝 )  ↔  ( 1st  ‘ 〈 𝑎 ,  𝑏 〉 )  <  ( 2nd  ‘ 〈 𝑎 ,  𝑏 〉 ) ) ) | 
						
							| 6 |  | vex | ⊢ 𝑎  ∈  V | 
						
							| 7 |  | vex | ⊢ 𝑏  ∈  V | 
						
							| 8 | 6 7 | op1st | ⊢ ( 1st  ‘ 〈 𝑎 ,  𝑏 〉 )  =  𝑎 | 
						
							| 9 | 6 7 | op2nd | ⊢ ( 2nd  ‘ 〈 𝑎 ,  𝑏 〉 )  =  𝑏 | 
						
							| 10 | 8 9 | breq12i | ⊢ ( ( 1st  ‘ 〈 𝑎 ,  𝑏 〉 )  <  ( 2nd  ‘ 〈 𝑎 ,  𝑏 〉 )  ↔  𝑎  <  𝑏 ) | 
						
							| 11 | 5 10 | bitrdi | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( ( 1st  ‘ 𝑝 )  <  ( 2nd  ‘ 𝑝 )  ↔  𝑎  <  𝑏 ) ) | 
						
							| 12 | 6 7 | op1std | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( 1st  ‘ 𝑝 )  =  𝑎 ) | 
						
							| 13 | 12 | oveq1d | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( ( 1st  ‘ 𝑝 ) ↑ 2 )  =  ( 𝑎 ↑ 2 ) ) | 
						
							| 14 | 6 7 | op2ndd | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( 2nd  ‘ 𝑝 )  =  𝑏 ) | 
						
							| 15 | 14 | oveq1d | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( ( 2nd  ‘ 𝑝 ) ↑ 2 )  =  ( 𝑏 ↑ 2 ) ) | 
						
							| 16 | 13 15 | oveq12d | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( ( ( 1st  ‘ 𝑝 ) ↑ 2 )  +  ( ( 2nd  ‘ 𝑝 ) ↑ 2 ) )  =  ( ( 𝑎 ↑ 2 )  +  ( 𝑏 ↑ 2 ) ) ) | 
						
							| 17 | 16 | eqeq1d | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( ( ( ( 1st  ‘ 𝑝 ) ↑ 2 )  +  ( ( 2nd  ‘ 𝑝 ) ↑ 2 ) )  =  𝑃  ↔  ( ( 𝑎 ↑ 2 )  +  ( 𝑏 ↑ 2 ) )  =  𝑃 ) ) | 
						
							| 18 | 11 17 | anbi12d | ⊢ ( 𝑝  =  〈 𝑎 ,  𝑏 〉  →  ( ( ( 1st  ‘ 𝑝 )  <  ( 2nd  ‘ 𝑝 )  ∧  ( ( ( 1st  ‘ 𝑝 ) ↑ 2 )  +  ( ( 2nd  ‘ 𝑝 ) ↑ 2 ) )  =  𝑃 )  ↔  ( 𝑎  <  𝑏  ∧  ( ( 𝑎 ↑ 2 )  +  ( 𝑏 ↑ 2 ) )  =  𝑃 ) ) ) | 
						
							| 19 | 18 | opreu2reurex | ⊢ ( ∃! 𝑝  ∈  ( ℕ0  ×  ℕ0 ) ( ( 1st  ‘ 𝑝 )  <  ( 2nd  ‘ 𝑝 )  ∧  ( ( ( 1st  ‘ 𝑝 ) ↑ 2 )  +  ( ( 2nd  ‘ 𝑝 ) ↑ 2 ) )  =  𝑃 )  ↔  ( ∃! 𝑎  ∈  ℕ0 ∃ 𝑏  ∈  ℕ0 ( 𝑎  <  𝑏  ∧  ( ( 𝑎 ↑ 2 )  +  ( 𝑏 ↑ 2 ) )  =  𝑃 )  ∧  ∃! 𝑏  ∈  ℕ0 ∃ 𝑎  ∈  ℕ0 ( 𝑎  <  𝑏  ∧  ( ( 𝑎 ↑ 2 )  +  ( 𝑏 ↑ 2 ) )  =  𝑃 ) ) ) | 
						
							| 20 | 2 19 | sylibr | ⊢ ( ( 𝑃  ∈  ℙ  ∧  ( 𝑃  mod  4 )  =  1 )  →  ∃! 𝑝  ∈  ( ℕ0  ×  ℕ0 ) ( ( 1st  ‘ 𝑝 )  <  ( 2nd  ‘ 𝑝 )  ∧  ( ( ( 1st  ‘ 𝑝 ) ↑ 2 )  +  ( ( 2nd  ‘ 𝑝 ) ↑ 2 ) )  =  𝑃 ) ) |