| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nna4b4nsq.a | ⊢ ( 𝜑  →  𝐴  ∈  ℕ ) | 
						
							| 2 |  | nna4b4nsq.b | ⊢ ( 𝜑  →  𝐵  ∈  ℕ ) | 
						
							| 3 |  | nna4b4nsq.c | ⊢ ( 𝜑  →  𝐶  ∈  ℕ ) | 
						
							| 4 |  | oveq1 | ⊢ ( 𝑎  =  𝐴  →  ( 𝑎 ↑ 4 )  =  ( 𝐴 ↑ 4 ) ) | 
						
							| 5 | 4 | oveq1d | ⊢ ( 𝑎  =  𝐴  →  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( ( 𝐴 ↑ 4 )  +  ( 𝑏 ↑ 4 ) ) ) | 
						
							| 6 | 5 | eqeq1d | ⊢ ( 𝑎  =  𝐴  →  ( ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 )  ↔  ( ( 𝐴 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) ) | 
						
							| 7 |  | oveq1 | ⊢ ( 𝑏  =  𝐵  →  ( 𝑏 ↑ 4 )  =  ( 𝐵 ↑ 4 ) ) | 
						
							| 8 | 7 | oveq2d | ⊢ ( 𝑏  =  𝐵  →  ( ( 𝐴 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) ) ) | 
						
							| 9 | 8 | eqeq1d | ⊢ ( 𝑏  =  𝐵  →  ( ( ( 𝐴 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 )  ↔  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) ) | 
						
							| 10 | 1 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑐  ∈  ℕ )  ∧  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) )  →  𝐴  ∈  ℕ ) | 
						
							| 11 | 2 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑐  ∈  ℕ )  ∧  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) )  →  𝐵  ∈  ℕ ) | 
						
							| 12 |  | simpr | ⊢ ( ( ( 𝜑  ∧  𝑐  ∈  ℕ )  ∧  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) )  →  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) | 
						
							| 13 | 6 9 10 11 12 | 2rspcedvdw | ⊢ ( ( ( 𝜑  ∧  𝑐  ∈  ℕ )  ∧  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) )  →  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) | 
						
							| 14 | 13 | ex | ⊢ ( ( 𝜑  ∧  𝑐  ∈  ℕ )  →  ( ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 )  →  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) ) | 
						
							| 15 | 14 | ss2rabdv | ⊢ ( 𝜑  →  { 𝑐  ∈  ℕ  ∣  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  ⊆  { 𝑐  ∈  ℕ  ∣  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) } ) | 
						
							| 16 |  | oveq1 | ⊢ ( 𝑓  =  𝑖  →  ( 𝑓 ↑ 2 )  =  ( 𝑖 ↑ 2 ) ) | 
						
							| 17 | 16 | eqeq2d | ⊢ ( 𝑓  =  𝑖  →  ( ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 )  ↔  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) | 
						
							| 18 | 17 | anbi2d | ⊢ ( 𝑓  =  𝑖  →  ( ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  ↔  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) ) | 
						
							| 19 | 18 | anbi2d | ⊢ ( 𝑓  =  𝑖  →  ( ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ↔  ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) ) ) | 
						
							| 20 | 19 | 2rexbidv | ⊢ ( 𝑓  =  𝑖  →  ( ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ↔  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) ) ) | 
						
							| 21 |  | oveq1 | ⊢ ( 𝑓  =  𝑙  →  ( 𝑓 ↑ 2 )  =  ( 𝑙 ↑ 2 ) ) | 
						
							| 22 | 21 | eqeq2d | ⊢ ( 𝑓  =  𝑙  →  ( ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 )  ↔  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑙 ↑ 2 ) ) ) | 
						
							| 23 | 22 | anbi2d | ⊢ ( 𝑓  =  𝑙  →  ( ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  ↔  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑙 ↑ 2 ) ) ) ) | 
						
							| 24 | 23 | anbi2d | ⊢ ( 𝑓  =  𝑙  →  ( ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ↔  ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑙 ↑ 2 ) ) ) ) ) | 
						
							| 25 | 24 | 2rexbidv | ⊢ ( 𝑓  =  𝑙  →  ( ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ↔  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑙 ↑ 2 ) ) ) ) ) | 
						
							| 26 |  | nnuz | ⊢ ℕ  =  ( ℤ≥ ‘ 1 ) | 
						
							| 27 | 26 | eqimssi | ⊢ ℕ  ⊆  ( ℤ≥ ‘ 1 ) | 
						
							| 28 | 27 | a1i | ⊢ ( 𝜑  →  ℕ  ⊆  ( ℤ≥ ‘ 1 ) ) | 
						
							| 29 |  | breq2 | ⊢ ( 𝑔  =  𝑗  →  ( 2  ∥  𝑔  ↔  2  ∥  𝑗 ) ) | 
						
							| 30 | 29 | notbid | ⊢ ( 𝑔  =  𝑗  →  ( ¬  2  ∥  𝑔  ↔  ¬  2  ∥  𝑗 ) ) | 
						
							| 31 |  | oveq1 | ⊢ ( 𝑔  =  𝑗  →  ( 𝑔  gcd  ℎ )  =  ( 𝑗  gcd  ℎ ) ) | 
						
							| 32 | 31 | eqeq1d | ⊢ ( 𝑔  =  𝑗  →  ( ( 𝑔  gcd  ℎ )  =  1  ↔  ( 𝑗  gcd  ℎ )  =  1 ) ) | 
						
							| 33 |  | oveq1 | ⊢ ( 𝑔  =  𝑗  →  ( 𝑔 ↑ 4 )  =  ( 𝑗 ↑ 4 ) ) | 
						
							| 34 | 33 | oveq1d | ⊢ ( 𝑔  =  𝑗  →  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( ( 𝑗 ↑ 4 )  +  ( ℎ ↑ 4 ) ) ) | 
						
							| 35 | 34 | eqeq1d | ⊢ ( 𝑔  =  𝑗  →  ( ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 )  ↔  ( ( 𝑗 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) | 
						
							| 36 | 32 35 | anbi12d | ⊢ ( 𝑔  =  𝑗  →  ( ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) )  ↔  ( ( 𝑗  gcd  ℎ )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) ) | 
						
							| 37 | 30 36 | anbi12d | ⊢ ( 𝑔  =  𝑗  →  ( ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) )  ↔  ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  ℎ )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) ) ) | 
						
							| 38 |  | oveq2 | ⊢ ( ℎ  =  𝑘  →  ( 𝑗  gcd  ℎ )  =  ( 𝑗  gcd  𝑘 ) ) | 
						
							| 39 | 38 | eqeq1d | ⊢ ( ℎ  =  𝑘  →  ( ( 𝑗  gcd  ℎ )  =  1  ↔  ( 𝑗  gcd  𝑘 )  =  1 ) ) | 
						
							| 40 |  | oveq1 | ⊢ ( ℎ  =  𝑘  →  ( ℎ ↑ 4 )  =  ( 𝑘 ↑ 4 ) ) | 
						
							| 41 | 40 | oveq2d | ⊢ ( ℎ  =  𝑘  →  ( ( 𝑗 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) ) ) | 
						
							| 42 | 41 | eqeq1d | ⊢ ( ℎ  =  𝑘  →  ( ( ( 𝑗 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 )  ↔  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) | 
						
							| 43 | 39 42 | anbi12d | ⊢ ( ℎ  =  𝑘  →  ( ( ( 𝑗  gcd  ℎ )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) )  ↔  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) ) | 
						
							| 44 | 43 | anbi2d | ⊢ ( ℎ  =  𝑘  →  ( ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  ℎ )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) )  ↔  ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) ) ) | 
						
							| 45 | 37 44 | cbvrex2vw | ⊢ ( ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) )  ↔  ∃ 𝑗  ∈  ℕ ∃ 𝑘  ∈  ℕ ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) ) | 
						
							| 46 |  | simplrl | ⊢ ( ( ( ( 𝜑  ∧  𝑖  ∈  ℕ )  ∧  ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ ) )  ∧  ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) )  →  𝑗  ∈  ℕ ) | 
						
							| 47 |  | simplrr | ⊢ ( ( ( ( 𝜑  ∧  𝑖  ∈  ℕ )  ∧  ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ ) )  ∧  ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) )  →  𝑘  ∈  ℕ ) | 
						
							| 48 |  | simpllr | ⊢ ( ( ( ( 𝜑  ∧  𝑖  ∈  ℕ )  ∧  ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ ) )  ∧  ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) )  →  𝑖  ∈  ℕ ) | 
						
							| 49 |  | simprl | ⊢ ( ( ( ( 𝜑  ∧  𝑖  ∈  ℕ )  ∧  ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ ) )  ∧  ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) )  →  ¬  2  ∥  𝑗 ) | 
						
							| 50 |  | simprrl | ⊢ ( ( ( ( 𝜑  ∧  𝑖  ∈  ℕ )  ∧  ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ ) )  ∧  ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) )  →  ( 𝑗  gcd  𝑘 )  =  1 ) | 
						
							| 51 |  | simprrr | ⊢ ( ( ( ( 𝜑  ∧  𝑖  ∈  ℕ )  ∧  ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ ) )  ∧  ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) )  →  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) | 
						
							| 52 | 46 47 48 49 50 51 | flt4lem7 | ⊢ ( ( ( ( 𝜑  ∧  𝑖  ∈  ℕ )  ∧  ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ ) )  ∧  ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) )  →  ∃ 𝑙  ∈  ℕ ( ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑙 ↑ 2 ) ) )  ∧  𝑙  <  𝑖 ) ) | 
						
							| 53 | 52 | ex | ⊢ ( ( ( 𝜑  ∧  𝑖  ∈  ℕ )  ∧  ( 𝑗  ∈  ℕ  ∧  𝑘  ∈  ℕ ) )  →  ( ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) )  →  ∃ 𝑙  ∈  ℕ ( ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑙 ↑ 2 ) ) )  ∧  𝑙  <  𝑖 ) ) ) | 
						
							| 54 | 53 | rexlimdvva | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ℕ )  →  ( ∃ 𝑗  ∈  ℕ ∃ 𝑘  ∈  ℕ ( ¬  2  ∥  𝑗  ∧  ( ( 𝑗  gcd  𝑘 )  =  1  ∧  ( ( 𝑗 ↑ 4 )  +  ( 𝑘 ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) )  →  ∃ 𝑙  ∈  ℕ ( ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑙 ↑ 2 ) ) )  ∧  𝑙  <  𝑖 ) ) ) | 
						
							| 55 | 45 54 | biimtrid | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ℕ )  →  ( ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) )  →  ∃ 𝑙  ∈  ℕ ( ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑙 ↑ 2 ) ) )  ∧  𝑙  <  𝑖 ) ) ) | 
						
							| 56 | 55 | impr | ⊢ ( ( 𝜑  ∧  ( 𝑖  ∈  ℕ  ∧  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑖 ↑ 2 ) ) ) ) )  →  ∃ 𝑙  ∈  ℕ ( ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑙 ↑ 2 ) ) )  ∧  𝑙  <  𝑖 ) ) | 
						
							| 57 | 20 25 28 56 | infdesc | ⊢ ( 𝜑  →  { 𝑓  ∈  ℕ  ∣  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) }  =  ∅ ) | 
						
							| 58 |  | breq2 | ⊢ ( 𝑔  =  𝑑  →  ( 2  ∥  𝑔  ↔  2  ∥  𝑑 ) ) | 
						
							| 59 | 58 | notbid | ⊢ ( 𝑔  =  𝑑  →  ( ¬  2  ∥  𝑔  ↔  ¬  2  ∥  𝑑 ) ) | 
						
							| 60 |  | oveq1 | ⊢ ( 𝑔  =  𝑑  →  ( 𝑔  gcd  ℎ )  =  ( 𝑑  gcd  ℎ ) ) | 
						
							| 61 | 60 | eqeq1d | ⊢ ( 𝑔  =  𝑑  →  ( ( 𝑔  gcd  ℎ )  =  1  ↔  ( 𝑑  gcd  ℎ )  =  1 ) ) | 
						
							| 62 |  | oveq1 | ⊢ ( 𝑔  =  𝑑  →  ( 𝑔 ↑ 4 )  =  ( 𝑑 ↑ 4 ) ) | 
						
							| 63 | 62 | oveq1d | ⊢ ( 𝑔  =  𝑑  →  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( ( 𝑑 ↑ 4 )  +  ( ℎ ↑ 4 ) ) ) | 
						
							| 64 | 63 | eqeq1d | ⊢ ( 𝑔  =  𝑑  →  ( ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 )  ↔  ( ( 𝑑 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) | 
						
							| 65 | 61 64 | anbi12d | ⊢ ( 𝑔  =  𝑑  →  ( ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  ↔  ( ( 𝑑  gcd  ℎ )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 66 | 59 65 | anbi12d | ⊢ ( 𝑔  =  𝑑  →  ( ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ↔  ( ¬  2  ∥  𝑑  ∧  ( ( 𝑑  gcd  ℎ )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) ) | 
						
							| 67 |  | oveq2 | ⊢ ( ℎ  =  𝑒  →  ( 𝑑  gcd  ℎ )  =  ( 𝑑  gcd  𝑒 ) ) | 
						
							| 68 | 67 | eqeq1d | ⊢ ( ℎ  =  𝑒  →  ( ( 𝑑  gcd  ℎ )  =  1  ↔  ( 𝑑  gcd  𝑒 )  =  1 ) ) | 
						
							| 69 |  | oveq1 | ⊢ ( ℎ  =  𝑒  →  ( ℎ ↑ 4 )  =  ( 𝑒 ↑ 4 ) ) | 
						
							| 70 | 69 | oveq2d | ⊢ ( ℎ  =  𝑒  →  ( ( 𝑑 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) ) ) | 
						
							| 71 | 70 | eqeq1d | ⊢ ( ℎ  =  𝑒  →  ( ( ( 𝑑 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 )  ↔  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) | 
						
							| 72 | 68 71 | anbi12d | ⊢ ( ℎ  =  𝑒  →  ( ( ( 𝑑  gcd  ℎ )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  ↔  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 73 | 72 | anbi2d | ⊢ ( ℎ  =  𝑒  →  ( ( ¬  2  ∥  𝑑  ∧  ( ( 𝑑  gcd  ℎ )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ↔  ( ¬  2  ∥  𝑑  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) ) | 
						
							| 74 |  | simprl | ⊢ ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  →  𝑑  ∈  ℕ ) | 
						
							| 75 | 74 | ad2antrr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑑 )  →  𝑑  ∈  ℕ ) | 
						
							| 76 |  | simprr | ⊢ ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  →  𝑒  ∈  ℕ ) | 
						
							| 77 | 76 | ad2antrr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑑 )  →  𝑒  ∈  ℕ ) | 
						
							| 78 |  | simpr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑑 )  →  ¬  2  ∥  𝑑 ) | 
						
							| 79 |  | simplr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑑 )  →  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) | 
						
							| 80 | 78 79 | jca | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑑 )  →  ( ¬  2  ∥  𝑑  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 81 | 66 73 75 77 80 | 2rspcedvdw | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑑 )  →  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 82 |  | breq2 | ⊢ ( 𝑔  =  𝑒  →  ( 2  ∥  𝑔  ↔  2  ∥  𝑒 ) ) | 
						
							| 83 | 82 | notbid | ⊢ ( 𝑔  =  𝑒  →  ( ¬  2  ∥  𝑔  ↔  ¬  2  ∥  𝑒 ) ) | 
						
							| 84 |  | oveq1 | ⊢ ( 𝑔  =  𝑒  →  ( 𝑔  gcd  ℎ )  =  ( 𝑒  gcd  ℎ ) ) | 
						
							| 85 | 84 | eqeq1d | ⊢ ( 𝑔  =  𝑒  →  ( ( 𝑔  gcd  ℎ )  =  1  ↔  ( 𝑒  gcd  ℎ )  =  1 ) ) | 
						
							| 86 |  | oveq1 | ⊢ ( 𝑔  =  𝑒  →  ( 𝑔 ↑ 4 )  =  ( 𝑒 ↑ 4 ) ) | 
						
							| 87 | 86 | oveq1d | ⊢ ( 𝑔  =  𝑒  →  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( ( 𝑒 ↑ 4 )  +  ( ℎ ↑ 4 ) ) ) | 
						
							| 88 | 87 | eqeq1d | ⊢ ( 𝑔  =  𝑒  →  ( ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 )  ↔  ( ( 𝑒 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) | 
						
							| 89 | 85 88 | anbi12d | ⊢ ( 𝑔  =  𝑒  →  ( ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  ↔  ( ( 𝑒  gcd  ℎ )  =  1  ∧  ( ( 𝑒 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 90 | 83 89 | anbi12d | ⊢ ( 𝑔  =  𝑒  →  ( ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ↔  ( ¬  2  ∥  𝑒  ∧  ( ( 𝑒  gcd  ℎ )  =  1  ∧  ( ( 𝑒 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) ) | 
						
							| 91 |  | oveq2 | ⊢ ( ℎ  =  𝑑  →  ( 𝑒  gcd  ℎ )  =  ( 𝑒  gcd  𝑑 ) ) | 
						
							| 92 | 91 | eqeq1d | ⊢ ( ℎ  =  𝑑  →  ( ( 𝑒  gcd  ℎ )  =  1  ↔  ( 𝑒  gcd  𝑑 )  =  1 ) ) | 
						
							| 93 |  | oveq1 | ⊢ ( ℎ  =  𝑑  →  ( ℎ ↑ 4 )  =  ( 𝑑 ↑ 4 ) ) | 
						
							| 94 | 93 | oveq2d | ⊢ ( ℎ  =  𝑑  →  ( ( 𝑒 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( ( 𝑒 ↑ 4 )  +  ( 𝑑 ↑ 4 ) ) ) | 
						
							| 95 | 94 | eqeq1d | ⊢ ( ℎ  =  𝑑  →  ( ( ( 𝑒 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 )  ↔  ( ( 𝑒 ↑ 4 )  +  ( 𝑑 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) | 
						
							| 96 | 92 95 | anbi12d | ⊢ ( ℎ  =  𝑑  →  ( ( ( 𝑒  gcd  ℎ )  =  1  ∧  ( ( 𝑒 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  ↔  ( ( 𝑒  gcd  𝑑 )  =  1  ∧  ( ( 𝑒 ↑ 4 )  +  ( 𝑑 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 97 | 96 | anbi2d | ⊢ ( ℎ  =  𝑑  →  ( ( ¬  2  ∥  𝑒  ∧  ( ( 𝑒  gcd  ℎ )  =  1  ∧  ( ( 𝑒 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ↔  ( ¬  2  ∥  𝑒  ∧  ( ( 𝑒  gcd  𝑑 )  =  1  ∧  ( ( 𝑒 ↑ 4 )  +  ( 𝑑 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) ) | 
						
							| 98 | 76 | ad2antrr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  𝑒  ∈  ℕ ) | 
						
							| 99 | 74 | ad2antrr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  𝑑  ∈  ℕ ) | 
						
							| 100 |  | simpr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ¬  2  ∥  𝑒 ) | 
						
							| 101 | 98 | nnzd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  𝑒  ∈  ℤ ) | 
						
							| 102 | 99 | nnzd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  𝑑  ∈  ℤ ) | 
						
							| 103 | 101 102 | gcdcomd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( 𝑒  gcd  𝑑 )  =  ( 𝑑  gcd  𝑒 ) ) | 
						
							| 104 |  | simplrl | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( 𝑑  gcd  𝑒 )  =  1 ) | 
						
							| 105 | 103 104 | eqtrd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( 𝑒  gcd  𝑑 )  =  1 ) | 
						
							| 106 |  | 4nn0 | ⊢ 4  ∈  ℕ0 | 
						
							| 107 | 106 | a1i | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  4  ∈  ℕ0 ) | 
						
							| 108 | 98 107 | nnexpcld | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( 𝑒 ↑ 4 )  ∈  ℕ ) | 
						
							| 109 | 108 | nncnd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( 𝑒 ↑ 4 )  ∈  ℂ ) | 
						
							| 110 | 99 107 | nnexpcld | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( 𝑑 ↑ 4 )  ∈  ℕ ) | 
						
							| 111 | 110 | nncnd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( 𝑑 ↑ 4 )  ∈  ℂ ) | 
						
							| 112 | 109 111 | addcomd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( ( 𝑒 ↑ 4 )  +  ( 𝑑 ↑ 4 ) )  =  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) ) ) | 
						
							| 113 |  | simplrr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) | 
						
							| 114 | 112 113 | eqtrd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( ( 𝑒 ↑ 4 )  +  ( 𝑑 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) | 
						
							| 115 | 100 105 114 | jca32 | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ( ¬  2  ∥  𝑒  ∧  ( ( 𝑒  gcd  𝑑 )  =  1  ∧  ( ( 𝑒 ↑ 4 )  +  ( 𝑑 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 116 | 90 97 98 99 115 | 2rspcedvdw | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  ¬  2  ∥  𝑒 )  →  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 117 | 74 | ad2antrr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  𝑑  ∈  ℕ ) | 
						
							| 118 | 117 | nnsqcld | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( 𝑑 ↑ 2 )  ∈  ℕ ) | 
						
							| 119 | 76 | ad2antrr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  𝑒  ∈  ℕ ) | 
						
							| 120 | 119 | nnsqcld | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( 𝑒 ↑ 2 )  ∈  ℕ ) | 
						
							| 121 |  | simp-4r | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  𝑓  ∈  ℕ ) | 
						
							| 122 |  | 2z | ⊢ 2  ∈  ℤ | 
						
							| 123 |  | simplrl | ⊢ ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  →  𝑑  ∈  ℕ ) | 
						
							| 124 | 123 | nnzd | ⊢ ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  →  𝑑  ∈  ℤ ) | 
						
							| 125 |  | 2nn | ⊢ 2  ∈  ℕ | 
						
							| 126 | 125 | a1i | ⊢ ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  →  2  ∈  ℕ ) | 
						
							| 127 |  | dvdsexp2im | ⊢ ( ( 2  ∈  ℤ  ∧  𝑑  ∈  ℤ  ∧  2  ∈  ℕ )  →  ( 2  ∥  𝑑  →  2  ∥  ( 𝑑 ↑ 2 ) ) ) | 
						
							| 128 | 122 124 126 127 | mp3an2i | ⊢ ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  →  ( 2  ∥  𝑑  →  2  ∥  ( 𝑑 ↑ 2 ) ) ) | 
						
							| 129 | 128 | imp | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  2  ∥  ( 𝑑 ↑ 2 ) ) | 
						
							| 130 |  | 2nn0 | ⊢ 2  ∈  ℕ0 | 
						
							| 131 | 130 | a1i | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  2  ∈  ℕ0 ) | 
						
							| 132 | 117 | nncnd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  𝑑  ∈  ℂ ) | 
						
							| 133 | 132 | flt4lem | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( 𝑑 ↑ 4 )  =  ( ( 𝑑 ↑ 2 ) ↑ 2 ) ) | 
						
							| 134 | 119 | nncnd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  𝑒  ∈  ℂ ) | 
						
							| 135 | 134 | flt4lem | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( 𝑒 ↑ 4 )  =  ( ( 𝑒 ↑ 2 ) ↑ 2 ) ) | 
						
							| 136 | 133 135 | oveq12d | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( ( 𝑑 ↑ 2 ) ↑ 2 )  +  ( ( 𝑒 ↑ 2 ) ↑ 2 ) ) ) | 
						
							| 137 |  | simplrr | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) | 
						
							| 138 | 136 137 | eqtr3d | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( ( ( 𝑑 ↑ 2 ) ↑ 2 )  +  ( ( 𝑒 ↑ 2 ) ↑ 2 ) )  =  ( 𝑓 ↑ 2 ) ) | 
						
							| 139 |  | simplrl | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( 𝑑  gcd  𝑒 )  =  1 ) | 
						
							| 140 | 125 | a1i | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  2  ∈  ℕ ) | 
						
							| 141 |  | rppwr | ⊢ ( ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ  ∧  2  ∈  ℕ )  →  ( ( 𝑑  gcd  𝑒 )  =  1  →  ( ( 𝑑 ↑ 2 )  gcd  ( 𝑒 ↑ 2 ) )  =  1 ) ) | 
						
							| 142 | 117 119 140 141 | syl3anc | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( ( 𝑑  gcd  𝑒 )  =  1  →  ( ( 𝑑 ↑ 2 )  gcd  ( 𝑒 ↑ 2 ) )  =  1 ) ) | 
						
							| 143 | 139 142 | mpd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( ( 𝑑 ↑ 2 )  gcd  ( 𝑒 ↑ 2 ) )  =  1 ) | 
						
							| 144 | 118 120 121 131 138 143 | fltaccoprm | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( ( 𝑑 ↑ 2 )  gcd  𝑓 )  =  1 ) | 
						
							| 145 | 118 120 121 129 144 138 | flt4lem2 | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ¬  2  ∥  ( 𝑒 ↑ 2 ) ) | 
						
							| 146 | 119 | nnzd | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  𝑒  ∈  ℤ ) | 
						
							| 147 |  | dvdsexp2im | ⊢ ( ( 2  ∈  ℤ  ∧  𝑒  ∈  ℤ  ∧  2  ∈  ℕ )  →  ( 2  ∥  𝑒  →  2  ∥  ( 𝑒 ↑ 2 ) ) ) | 
						
							| 148 | 122 146 140 147 | mp3an2i | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ( 2  ∥  𝑒  →  2  ∥  ( 𝑒 ↑ 2 ) ) ) | 
						
							| 149 | 145 148 | mtod | ⊢ ( ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ∧  2  ∥  𝑑 )  →  ¬  2  ∥  𝑒 ) | 
						
							| 150 | 149 | ex | ⊢ ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  →  ( 2  ∥  𝑑  →  ¬  2  ∥  𝑒 ) ) | 
						
							| 151 |  | imor | ⊢ ( ( 2  ∥  𝑑  →  ¬  2  ∥  𝑒 )  ↔  ( ¬  2  ∥  𝑑  ∨  ¬  2  ∥  𝑒 ) ) | 
						
							| 152 | 150 151 | sylib | ⊢ ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  →  ( ¬  2  ∥  𝑑  ∨  ¬  2  ∥  𝑒 ) ) | 
						
							| 153 | 81 116 152 | mpjaodan | ⊢ ( ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  ∧  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  →  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 154 | 153 | ex | ⊢ ( ( ( 𝜑  ∧  𝑓  ∈  ℕ )  ∧  ( 𝑑  ∈  ℕ  ∧  𝑒  ∈  ℕ ) )  →  ( ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  →  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) ) | 
						
							| 155 | 154 | rexlimdvva | ⊢ ( ( 𝜑  ∧  𝑓  ∈  ℕ )  →  ( ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  →  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) ) | 
						
							| 156 | 155 | reximdva | ⊢ ( 𝜑  →  ( ∃ 𝑓  ∈  ℕ ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  →  ∃ 𝑓  ∈  ℕ ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) ) | 
						
							| 157 | 156 | con3d | ⊢ ( 𝜑  →  ( ¬  ∃ 𝑓  ∈  ℕ ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  →  ¬  ∃ 𝑓  ∈  ℕ ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 158 |  | ralnex | ⊢ ( ∀ 𝑓  ∈  ℕ ¬  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  ↔  ¬  ∃ 𝑓  ∈  ℕ ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 159 |  | ralnex | ⊢ ( ∀ 𝑓  ∈  ℕ ¬  ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  ↔  ¬  ∃ 𝑓  ∈  ℕ ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) | 
						
							| 160 | 157 158 159 | 3imtr4g | ⊢ ( 𝜑  →  ( ∀ 𝑓  ∈  ℕ ¬  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) )  →  ∀ 𝑓  ∈  ℕ ¬  ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 161 |  | rabeq0 | ⊢ ( { 𝑓  ∈  ℕ  ∣  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) }  =  ∅  ↔  ∀ 𝑓  ∈  ℕ ¬  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 162 |  | rabeq0 | ⊢ ( { 𝑓  ∈  ℕ  ∣  ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) }  =  ∅  ↔  ∀ 𝑓  ∈  ℕ ¬  ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) | 
						
							| 163 | 160 161 162 | 3imtr4g | ⊢ ( 𝜑  →  ( { 𝑓  ∈  ℕ  ∣  ∃ 𝑔  ∈  ℕ ∃ ℎ  ∈  ℕ ( ¬  2  ∥  𝑔  ∧  ( ( 𝑔  gcd  ℎ )  =  1  ∧  ( ( 𝑔 ↑ 4 )  +  ( ℎ ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) }  =  ∅  →  { 𝑓  ∈  ℕ  ∣  ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) }  =  ∅ ) ) | 
						
							| 164 | 57 163 | mpd | ⊢ ( 𝜑  →  { 𝑓  ∈  ℕ  ∣  ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) }  =  ∅ ) | 
						
							| 165 |  | oveq1 | ⊢ ( 𝑓  =  ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) )  →  ( 𝑓 ↑ 2 )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) | 
						
							| 166 | 165 | eqeq2d | ⊢ ( 𝑓  =  ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) )  →  ( ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 )  ↔  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) ) | 
						
							| 167 | 166 | anbi2d | ⊢ ( 𝑓  =  ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) )  →  ( ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  ↔  ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) ) ) | 
						
							| 168 |  | oveq1 | ⊢ ( 𝑑  =  ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  →  ( 𝑑  gcd  𝑒 )  =  ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  𝑒 ) ) | 
						
							| 169 | 168 | eqeq1d | ⊢ ( 𝑑  =  ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  →  ( ( 𝑑  gcd  𝑒 )  =  1  ↔  ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  𝑒 )  =  1 ) ) | 
						
							| 170 |  | oveq1 | ⊢ ( 𝑑  =  ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  →  ( 𝑑 ↑ 4 )  =  ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 ) ) | 
						
							| 171 | 170 | oveq1d | ⊢ ( 𝑑  =  ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  →  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( 𝑒 ↑ 4 ) ) ) | 
						
							| 172 | 171 | eqeq1d | ⊢ ( 𝑑  =  ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  →  ( ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 )  ↔  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) ) | 
						
							| 173 | 169 172 | anbi12d | ⊢ ( 𝑑  =  ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  →  ( ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) )  ↔  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  𝑒 )  =  1  ∧  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) ) ) | 
						
							| 174 |  | oveq2 | ⊢ ( 𝑒  =  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) )  →  ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  𝑒 )  =  ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) ) ) | 
						
							| 175 | 174 | eqeq1d | ⊢ ( 𝑒  =  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) )  →  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  𝑒 )  =  1  ↔  ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) )  =  1 ) ) | 
						
							| 176 |  | oveq1 | ⊢ ( 𝑒  =  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) )  →  ( 𝑒 ↑ 4 )  =  ( ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 ) ) | 
						
							| 177 | 176 | oveq2d | ⊢ ( 𝑒  =  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) )  →  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 ) ) ) | 
						
							| 178 | 177 | eqeq1d | ⊢ ( 𝑒  =  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) )  →  ( ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 )  ↔  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) ) | 
						
							| 179 | 175 178 | anbi12d | ⊢ ( 𝑒  =  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) )  →  ( ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  𝑒 )  =  1  ∧  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) )  ↔  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) )  =  1  ∧  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) ) ) | 
						
							| 180 |  | simplrr | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  𝑎  ∈  ℕ ) | 
						
							| 181 |  | simprl | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  𝑏  ∈  ℕ ) | 
						
							| 182 |  | simplrl | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  𝑐  ∈  ℕ ) | 
						
							| 183 |  | simprr | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) | 
						
							| 184 | 180 181 182 183 | flt4lem6 | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  ∈  ℕ  ∧  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) )  ∈  ℕ  ∧  ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) )  ∈  ℕ )  ∧  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) ) | 
						
							| 185 | 184 | simpld | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  ∈  ℕ  ∧  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) )  ∈  ℕ  ∧  ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) )  ∈  ℕ ) ) | 
						
							| 186 | 185 | simp3d | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) )  ∈  ℕ ) | 
						
							| 187 | 185 | simp1d | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  ∈  ℕ ) | 
						
							| 188 | 185 | simp2d | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) )  ∈  ℕ ) | 
						
							| 189 | 180 | nnzd | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  𝑎  ∈  ℤ ) | 
						
							| 190 | 181 | nnzd | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  𝑏  ∈  ℤ ) | 
						
							| 191 | 181 | nnne0d | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  𝑏  ≠  0 ) | 
						
							| 192 |  | divgcdcoprm0 | ⊢ ( ( 𝑎  ∈  ℤ  ∧  𝑏  ∈  ℤ  ∧  𝑏  ≠  0 )  →  ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) )  =  1 ) | 
						
							| 193 | 189 190 191 192 | syl3anc | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) )  =  1 ) | 
						
							| 194 | 184 | simprd | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) | 
						
							| 195 | 193 194 | jca | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) )  gcd  ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) )  =  1  ∧  ( ( ( 𝑎  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 )  +  ( ( 𝑏  /  ( 𝑎  gcd  𝑏 ) ) ↑ 4 ) )  =  ( ( 𝑐  /  ( ( 𝑎  gcd  𝑏 ) ↑ 2 ) ) ↑ 2 ) ) ) | 
						
							| 196 | 167 173 179 186 187 188 195 | 3rspcedvdw | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  ∧  ( 𝑏  ∈  ℕ  ∧  ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) )  →  ∃ 𝑓  ∈  ℕ ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) | 
						
							| 197 | 196 | rexlimdvaa | ⊢ ( ( 𝜑  ∧  ( 𝑐  ∈  ℕ  ∧  𝑎  ∈  ℕ ) )  →  ( ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 )  →  ∃ 𝑓  ∈  ℕ ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 198 | 197 | rexlimdvva | ⊢ ( 𝜑  →  ( ∃ 𝑐  ∈  ℕ ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 )  →  ∃ 𝑓  ∈  ℕ ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) ) ) | 
						
							| 199 | 198 | con3d | ⊢ ( 𝜑  →  ( ¬  ∃ 𝑓  ∈  ℕ ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  →  ¬  ∃ 𝑐  ∈  ℕ ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) ) | 
						
							| 200 |  | ralnex | ⊢ ( ∀ 𝑐  ∈  ℕ ¬  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 )  ↔  ¬  ∃ 𝑐  ∈  ℕ ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) | 
						
							| 201 | 199 159 200 | 3imtr4g | ⊢ ( 𝜑  →  ( ∀ 𝑓  ∈  ℕ ¬  ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) )  →  ∀ 𝑐  ∈  ℕ ¬  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) ) | 
						
							| 202 |  | rabeq0 | ⊢ ( { 𝑐  ∈  ℕ  ∣  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  =  ∅  ↔  ∀ 𝑐  ∈  ℕ ¬  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) | 
						
							| 203 | 201 162 202 | 3imtr4g | ⊢ ( 𝜑  →  ( { 𝑓  ∈  ℕ  ∣  ∃ 𝑑  ∈  ℕ ∃ 𝑒  ∈  ℕ ( ( 𝑑  gcd  𝑒 )  =  1  ∧  ( ( 𝑑 ↑ 4 )  +  ( 𝑒 ↑ 4 ) )  =  ( 𝑓 ↑ 2 ) ) }  =  ∅  →  { 𝑐  ∈  ℕ  ∣  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  =  ∅ ) ) | 
						
							| 204 | 164 203 | mpd | ⊢ ( 𝜑  →  { 𝑐  ∈  ℕ  ∣  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  =  ∅ ) | 
						
							| 205 |  | sseq0 | ⊢ ( ( { 𝑐  ∈  ℕ  ∣  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  ⊆  { 𝑐  ∈  ℕ  ∣  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  ∧  { 𝑐  ∈  ℕ  ∣  ∃ 𝑎  ∈  ℕ ∃ 𝑏  ∈  ℕ ( ( 𝑎 ↑ 4 )  +  ( 𝑏 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  =  ∅ )  →  { 𝑐  ∈  ℕ  ∣  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  =  ∅ ) | 
						
							| 206 | 15 204 205 | syl2anc | ⊢ ( 𝜑  →  { 𝑐  ∈  ℕ  ∣  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  =  ∅ ) | 
						
							| 207 |  | rabeq0 | ⊢ ( { 𝑐  ∈  ℕ  ∣  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) }  =  ∅  ↔  ∀ 𝑐  ∈  ℕ ¬  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) | 
						
							| 208 | 206 207 | sylib | ⊢ ( 𝜑  →  ∀ 𝑐  ∈  ℕ ¬  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 ) ) | 
						
							| 209 |  | oveq1 | ⊢ ( 𝑐  =  𝐶  →  ( 𝑐 ↑ 2 )  =  ( 𝐶 ↑ 2 ) ) | 
						
							| 210 | 209 | eqeq2d | ⊢ ( 𝑐  =  𝐶  →  ( ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 )  ↔  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝐶 ↑ 2 ) ) ) | 
						
							| 211 | 210 | necon3bbid | ⊢ ( 𝑐  =  𝐶  →  ( ¬  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 )  ↔  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  ≠  ( 𝐶 ↑ 2 ) ) ) | 
						
							| 212 | 211 | rspcv | ⊢ ( 𝐶  ∈  ℕ  →  ( ∀ 𝑐  ∈  ℕ ¬  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  =  ( 𝑐 ↑ 2 )  →  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  ≠  ( 𝐶 ↑ 2 ) ) ) | 
						
							| 213 | 3 208 212 | sylc | ⊢ ( 𝜑  →  ( ( 𝐴 ↑ 4 )  +  ( 𝐵 ↑ 4 ) )  ≠  ( 𝐶 ↑ 2 ) ) |