| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eropr.1 | ⊢ 𝐽  =  ( 𝐴  /  𝑅 ) | 
						
							| 2 |  | eropr.2 | ⊢ 𝐾  =  ( 𝐵  /  𝑆 ) | 
						
							| 3 |  | eropr.3 | ⊢ ( 𝜑  →  𝑇  ∈  𝑍 ) | 
						
							| 4 |  | eropr.4 | ⊢ ( 𝜑  →  𝑅  Er  𝑈 ) | 
						
							| 5 |  | eropr.5 | ⊢ ( 𝜑  →  𝑆  Er  𝑉 ) | 
						
							| 6 |  | eropr.6 | ⊢ ( 𝜑  →  𝑇  Er  𝑊 ) | 
						
							| 7 |  | eropr.7 | ⊢ ( 𝜑  →  𝐴  ⊆  𝑈 ) | 
						
							| 8 |  | eropr.8 | ⊢ ( 𝜑  →  𝐵  ⊆  𝑉 ) | 
						
							| 9 |  | eropr.9 | ⊢ ( 𝜑  →  𝐶  ⊆  𝑊 ) | 
						
							| 10 |  | eropr.10 | ⊢ ( 𝜑  →   +  : ( 𝐴  ×  𝐵 ) ⟶ 𝐶 ) | 
						
							| 11 |  | eropr.11 | ⊢ ( ( 𝜑  ∧  ( ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 )  ∧  ( 𝑡  ∈  𝐵  ∧  𝑢  ∈  𝐵 ) ) )  →  ( ( 𝑟 𝑅 𝑠  ∧  𝑡 𝑆 𝑢 )  →  ( 𝑟  +  𝑡 ) 𝑇 ( 𝑠  +  𝑢 ) ) ) | 
						
							| 12 |  | eropr.12 | ⊢  ⨣   =  { 〈 〈 𝑥 ,  𝑦 〉 ,  𝑧 〉  ∣  ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) } | 
						
							| 13 |  | eropr.13 | ⊢ ( 𝜑  →  𝑅  ∈  𝑋 ) | 
						
							| 14 |  | eropr.14 | ⊢ ( 𝜑  →  𝑆  ∈  𝑌 ) | 
						
							| 15 |  | eropr.15 | ⊢ 𝐿  =  ( 𝐶  /  𝑇 ) | 
						
							| 16 | 3 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  ∧  ( 𝑝  ∈  𝐴  ∧  𝑞  ∈  𝐵 ) )  →  𝑇  ∈  𝑍 ) | 
						
							| 17 | 10 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  →   +  : ( 𝐴  ×  𝐵 ) ⟶ 𝐶 ) | 
						
							| 18 | 17 | fovcdmda | ⊢ ( ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  ∧  ( 𝑝  ∈  𝐴  ∧  𝑞  ∈  𝐵 ) )  →  ( 𝑝  +  𝑞 )  ∈  𝐶 ) | 
						
							| 19 |  | ecelqsg | ⊢ ( ( 𝑇  ∈  𝑍  ∧  ( 𝑝  +  𝑞 )  ∈  𝐶 )  →  [ ( 𝑝  +  𝑞 ) ] 𝑇  ∈  ( 𝐶  /  𝑇 ) ) | 
						
							| 20 | 16 18 19 | syl2anc | ⊢ ( ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  ∧  ( 𝑝  ∈  𝐴  ∧  𝑞  ∈  𝐵 ) )  →  [ ( 𝑝  +  𝑞 ) ] 𝑇  ∈  ( 𝐶  /  𝑇 ) ) | 
						
							| 21 | 20 15 | eleqtrrdi | ⊢ ( ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  ∧  ( 𝑝  ∈  𝐴  ∧  𝑞  ∈  𝐵 ) )  →  [ ( 𝑝  +  𝑞 ) ] 𝑇  ∈  𝐿 ) | 
						
							| 22 |  | eleq1a | ⊢ ( [ ( 𝑝  +  𝑞 ) ] 𝑇  ∈  𝐿  →  ( 𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇  →  𝑧  ∈  𝐿 ) ) | 
						
							| 23 | 21 22 | syl | ⊢ ( ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  ∧  ( 𝑝  ∈  𝐴  ∧  𝑞  ∈  𝐵 ) )  →  ( 𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇  →  𝑧  ∈  𝐿 ) ) | 
						
							| 24 | 23 | adantld | ⊢ ( ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  ∧  ( 𝑝  ∈  𝐴  ∧  𝑞  ∈  𝐵 ) )  →  ( ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 )  →  𝑧  ∈  𝐿 ) ) | 
						
							| 25 | 24 | rexlimdvva | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  →  ( ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 )  →  𝑧  ∈  𝐿 ) ) | 
						
							| 26 | 25 | abssdv | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  →  { 𝑧  ∣  ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) }  ⊆  𝐿 ) | 
						
							| 27 | 1 2 3 4 5 6 7 8 9 10 11 | eroveu | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  →  ∃! 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) ) | 
						
							| 28 |  | iotacl | ⊢ ( ∃! 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 )  →  ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) )  ∈  { 𝑧  ∣  ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) } ) | 
						
							| 29 | 27 28 | syl | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  →  ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) )  ∈  { 𝑧  ∣  ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) } ) | 
						
							| 30 | 26 29 | sseldd | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐽  ∧  𝑦  ∈  𝐾 ) )  →  ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) )  ∈  𝐿 ) | 
						
							| 31 | 30 | ralrimivva | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐽 ∀ 𝑦  ∈  𝐾 ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) )  ∈  𝐿 ) | 
						
							| 32 |  | eqid | ⊢ ( 𝑥  ∈  𝐽 ,  𝑦  ∈  𝐾  ↦  ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) ) )  =  ( 𝑥  ∈  𝐽 ,  𝑦  ∈  𝐾  ↦  ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) ) ) | 
						
							| 33 | 32 | fmpo | ⊢ ( ∀ 𝑥  ∈  𝐽 ∀ 𝑦  ∈  𝐾 ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) )  ∈  𝐿  ↔  ( 𝑥  ∈  𝐽 ,  𝑦  ∈  𝐾  ↦  ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) ) ) : ( 𝐽  ×  𝐾 ) ⟶ 𝐿 ) | 
						
							| 34 | 31 33 | sylib | ⊢ ( 𝜑  →  ( 𝑥  ∈  𝐽 ,  𝑦  ∈  𝐾  ↦  ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) ) ) : ( 𝐽  ×  𝐾 ) ⟶ 𝐿 ) | 
						
							| 35 | 1 2 3 4 5 6 7 8 9 10 11 12 | erovlem | ⊢ ( 𝜑  →   ⨣   =  ( 𝑥  ∈  𝐽 ,  𝑦  ∈  𝐾  ↦  ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) ) ) ) | 
						
							| 36 | 35 | feq1d | ⊢ ( 𝜑  →  (  ⨣  : ( 𝐽  ×  𝐾 ) ⟶ 𝐿  ↔  ( 𝑥  ∈  𝐽 ,  𝑦  ∈  𝐾  ↦  ( ℩ 𝑧 ∃ 𝑝  ∈  𝐴 ∃ 𝑞  ∈  𝐵 ( ( 𝑥  =  [ 𝑝 ] 𝑅  ∧  𝑦  =  [ 𝑞 ] 𝑆 )  ∧  𝑧  =  [ ( 𝑝  +  𝑞 ) ] 𝑇 ) ) ) : ( 𝐽  ×  𝐾 ) ⟶ 𝐿 ) ) | 
						
							| 37 | 34 36 | mpbird | ⊢ ( 𝜑  →   ⨣  : ( 𝐽  ×  𝐾 ) ⟶ 𝐿 ) |