| Step | Hyp | Ref | Expression | 
						
							| 1 |  | el2mpocsbcl.o | ⊢ 𝑂  =  ( 𝑥  ∈  𝐴 ,  𝑦  ∈  𝐵  ↦  ( 𝑠  ∈  𝐶 ,  𝑡  ∈  𝐷  ↦  𝐸 ) ) | 
						
							| 2 |  | simpl | ⊢ ( ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 ) ) )  →  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) ) | 
						
							| 3 |  | nfcv | ⊢ Ⅎ 𝑎 ( 𝑠  ∈  𝐶 ,  𝑡  ∈  𝐷  ↦  𝐸 ) | 
						
							| 4 |  | nfcv | ⊢ Ⅎ 𝑏 ( 𝑠  ∈  𝐶 ,  𝑡  ∈  𝐷  ↦  𝐸 ) | 
						
							| 5 |  | nfcsb1v | ⊢ Ⅎ 𝑥 ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 | 
						
							| 6 |  | nfcsb1v | ⊢ Ⅎ 𝑥 ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷 | 
						
							| 7 |  | nfcsb1v | ⊢ Ⅎ 𝑥 ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 | 
						
							| 8 | 5 6 7 | nfmpo | ⊢ Ⅎ 𝑥 ( 𝑠  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) | 
						
							| 9 |  | nfcv | ⊢ Ⅎ 𝑦 𝑎 | 
						
							| 10 |  | nfcsb1v | ⊢ Ⅎ 𝑦 ⦋ 𝑏  /  𝑦 ⦌ 𝐶 | 
						
							| 11 | 9 10 | nfcsbw | ⊢ Ⅎ 𝑦 ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 | 
						
							| 12 |  | nfcsb1v | ⊢ Ⅎ 𝑦 ⦋ 𝑏  /  𝑦 ⦌ 𝐷 | 
						
							| 13 | 9 12 | nfcsbw | ⊢ Ⅎ 𝑦 ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷 | 
						
							| 14 |  | nfcsb1v | ⊢ Ⅎ 𝑦 ⦋ 𝑏  /  𝑦 ⦌ 𝐸 | 
						
							| 15 | 9 14 | nfcsbw | ⊢ Ⅎ 𝑦 ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 | 
						
							| 16 | 11 13 15 | nfmpo | ⊢ Ⅎ 𝑦 ( 𝑠  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) | 
						
							| 17 |  | csbeq1a | ⊢ ( 𝑥  =  𝑎  →  𝐶  =  ⦋ 𝑎  /  𝑥 ⦌ 𝐶 ) | 
						
							| 18 |  | csbeq1a | ⊢ ( 𝑦  =  𝑏  →  𝐶  =  ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ) | 
						
							| 19 | 18 | csbeq2dv | ⊢ ( 𝑦  =  𝑏  →  ⦋ 𝑎  /  𝑥 ⦌ 𝐶  =  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ) | 
						
							| 20 | 17 19 | sylan9eq | ⊢ ( ( 𝑥  =  𝑎  ∧  𝑦  =  𝑏 )  →  𝐶  =  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ) | 
						
							| 21 |  | csbeq1a | ⊢ ( 𝑥  =  𝑎  →  𝐷  =  ⦋ 𝑎  /  𝑥 ⦌ 𝐷 ) | 
						
							| 22 |  | csbeq1a | ⊢ ( 𝑦  =  𝑏  →  𝐷  =  ⦋ 𝑏  /  𝑦 ⦌ 𝐷 ) | 
						
							| 23 | 22 | csbeq2dv | ⊢ ( 𝑦  =  𝑏  →  ⦋ 𝑎  /  𝑥 ⦌ 𝐷  =  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷 ) | 
						
							| 24 | 21 23 | sylan9eq | ⊢ ( ( 𝑥  =  𝑎  ∧  𝑦  =  𝑏 )  →  𝐷  =  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷 ) | 
						
							| 25 |  | csbeq1a | ⊢ ( 𝑥  =  𝑎  →  𝐸  =  ⦋ 𝑎  /  𝑥 ⦌ 𝐸 ) | 
						
							| 26 |  | csbeq1a | ⊢ ( 𝑦  =  𝑏  →  𝐸  =  ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) | 
						
							| 27 | 26 | csbeq2dv | ⊢ ( 𝑦  =  𝑏  →  ⦋ 𝑎  /  𝑥 ⦌ 𝐸  =  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) | 
						
							| 28 | 25 27 | sylan9eq | ⊢ ( ( 𝑥  =  𝑎  ∧  𝑦  =  𝑏 )  →  𝐸  =  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) | 
						
							| 29 | 20 24 28 | mpoeq123dv | ⊢ ( ( 𝑥  =  𝑎  ∧  𝑦  =  𝑏 )  →  ( 𝑠  ∈  𝐶 ,  𝑡  ∈  𝐷  ↦  𝐸 )  =  ( 𝑠  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) ) | 
						
							| 30 | 3 4 8 16 29 | cbvmpo | ⊢ ( 𝑥  ∈  𝐴 ,  𝑦  ∈  𝐵  ↦  ( 𝑠  ∈  𝐶 ,  𝑡  ∈  𝐷  ↦  𝐸 ) )  =  ( 𝑎  ∈  𝐴 ,  𝑏  ∈  𝐵  ↦  ( 𝑠  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) ) | 
						
							| 31 | 1 30 | eqtri | ⊢ 𝑂  =  ( 𝑎  ∈  𝐴 ,  𝑏  ∈  𝐵  ↦  ( 𝑠  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) ) | 
						
							| 32 | 31 | a1i | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  𝑂  =  ( 𝑎  ∈  𝐴 ,  𝑏  ∈  𝐵  ↦  ( 𝑠  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) ) ) | 
						
							| 33 |  | csbeq1 | ⊢ ( 𝑎  =  𝑋  →  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ) | 
						
							| 34 | 33 | adantr | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ) | 
						
							| 35 |  | csbeq1 | ⊢ ( 𝑏  =  𝑌  →  ⦋ 𝑏  /  𝑦 ⦌ 𝐶  =  ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ) | 
						
							| 36 | 35 | adantl | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑏  /  𝑦 ⦌ 𝐶  =  ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ) | 
						
							| 37 | 36 | csbeq2dv | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ) | 
						
							| 38 | 34 37 | eqtrd | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ) | 
						
							| 39 |  | csbeq1 | ⊢ ( 𝑎  =  𝑋  →  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷 ) | 
						
							| 40 | 39 | adantr | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷 ) | 
						
							| 41 |  | csbeq1 | ⊢ ( 𝑏  =  𝑌  →  ⦋ 𝑏  /  𝑦 ⦌ 𝐷  =  ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) | 
						
							| 42 | 41 | adantl | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑏  /  𝑦 ⦌ 𝐷  =  ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) | 
						
							| 43 | 42 | csbeq2dv | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) | 
						
							| 44 | 40 43 | eqtrd | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) | 
						
							| 45 |  | csbeq1 | ⊢ ( 𝑎  =  𝑋  →  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) | 
						
							| 46 | 45 | adantr | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 ) | 
						
							| 47 |  | csbeq1 | ⊢ ( 𝑏  =  𝑌  →  ⦋ 𝑏  /  𝑦 ⦌ 𝐸  =  ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) | 
						
							| 48 | 47 | adantl | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑏  /  𝑦 ⦌ 𝐸  =  ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) | 
						
							| 49 | 48 | csbeq2dv | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) | 
						
							| 50 | 46 49 | eqtrd | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸  =  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) | 
						
							| 51 | 38 44 50 | mpoeq123dv | ⊢ ( ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 )  →  ( 𝑠  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 )  =  ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) ) | 
						
							| 52 | 51 | adantl | ⊢ ( ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  ∧  ( 𝑎  =  𝑋  ∧  𝑏  =  𝑌 ) )  →  ( 𝑠  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑎  /  𝑥 ⦌ ⦋ 𝑏  /  𝑦 ⦌ 𝐸 )  =  ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) ) | 
						
							| 53 |  | simpl | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  𝑋  ∈  𝐴 ) | 
						
							| 54 | 53 | adantl | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  𝑋  ∈  𝐴 ) | 
						
							| 55 |  | simpr | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  𝑌  ∈  𝐵 ) | 
						
							| 56 | 55 | adantl | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  𝑌  ∈  𝐵 ) | 
						
							| 57 |  | simpl | ⊢ ( ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  →  𝐶  ∈  𝑈 ) | 
						
							| 58 | 57 | ralimi | ⊢ ( ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  →  ∀ 𝑦  ∈  𝐵 𝐶  ∈  𝑈 ) | 
						
							| 59 |  | rspcsbela | ⊢ ( ( 𝑌  ∈  𝐵  ∧  ∀ 𝑦  ∈  𝐵 𝐶  ∈  𝑈 )  →  ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∈  𝑈 ) | 
						
							| 60 | 55 58 59 | syl2an | ⊢ ( ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 ) )  →  ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∈  𝑈 ) | 
						
							| 61 | 60 | ex | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  →  ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∈  𝑈 ) ) | 
						
							| 62 | 61 | ralimdv | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  →  ∀ 𝑥  ∈  𝐴 ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∈  𝑈 ) ) | 
						
							| 63 | 62 | impcom | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  ∀ 𝑥  ∈  𝐴 ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∈  𝑈 ) | 
						
							| 64 |  | rspcsbela | ⊢ ( ( 𝑋  ∈  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∈  𝑈 )  →  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∈  𝑈 ) | 
						
							| 65 | 54 63 64 | syl2anc | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∈  𝑈 ) | 
						
							| 66 |  | simpr | ⊢ ( ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  →  𝐷  ∈  𝑉 ) | 
						
							| 67 | 66 | ralimi | ⊢ ( ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  →  ∀ 𝑦  ∈  𝐵 𝐷  ∈  𝑉 ) | 
						
							| 68 |  | rspcsbela | ⊢ ( ( 𝑌  ∈  𝐵  ∧  ∀ 𝑦  ∈  𝐵 𝐷  ∈  𝑉 )  →  ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ∈  𝑉 ) | 
						
							| 69 | 55 67 68 | syl2an | ⊢ ( ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 ) )  →  ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ∈  𝑉 ) | 
						
							| 70 | 69 | ex | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  →  ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ∈  𝑉 ) ) | 
						
							| 71 | 70 | ralimdv | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  →  ∀ 𝑥  ∈  𝐴 ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ∈  𝑉 ) ) | 
						
							| 72 | 71 | impcom | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  ∀ 𝑥  ∈  𝐴 ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ∈  𝑉 ) | 
						
							| 73 |  | rspcsbela | ⊢ ( ( 𝑋  ∈  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ∈  𝑉 )  →  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ∈  𝑉 ) | 
						
							| 74 | 54 72 73 | syl2anc | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ∈  𝑉 ) | 
						
							| 75 |  | mpoexga | ⊢ ( ( ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∈  𝑈  ∧  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ∈  𝑉 )  →  ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 )  ∈  V ) | 
						
							| 76 | 65 74 75 | syl2anc | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 )  ∈  V ) | 
						
							| 77 | 32 52 54 56 76 | ovmpod | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  ( 𝑋 𝑂 𝑌 )  =  ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) ) | 
						
							| 78 | 77 | oveqd | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 )  =  ( 𝑆 ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) 𝑇 ) ) | 
						
							| 79 | 78 | eleq2d | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  ( 𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 )  ↔  𝑊  ∈  ( 𝑆 ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) 𝑇 ) ) ) | 
						
							| 80 |  | eqid | ⊢ ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 )  =  ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) | 
						
							| 81 | 80 | elmpocl | ⊢ ( 𝑊  ∈  ( 𝑆 ( 𝑠  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶 ,  𝑡  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷  ↦  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐸 ) 𝑇 )  →  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) | 
						
							| 82 | 79 81 | biimtrdi | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 ) )  →  ( 𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 )  →  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) | 
						
							| 83 | 82 | impancom | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 ) )  →  ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) | 
						
							| 84 | 83 | impcom | ⊢ ( ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 ) ) )  →  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) | 
						
							| 85 | 2 84 | jca | ⊢ ( ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 ) ) )  →  ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) | 
						
							| 86 | 85 | ex | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 ) )  →  ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) ) | 
						
							| 87 | 1 | mpondm0 | ⊢ ( ¬  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( 𝑋 𝑂 𝑌 )  =  ∅ ) | 
						
							| 88 | 87 | oveqd | ⊢ ( ¬  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 )  =  ( 𝑆 ∅ 𝑇 ) ) | 
						
							| 89 | 88 | eleq2d | ⊢ ( ¬  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( 𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 )  ↔  𝑊  ∈  ( 𝑆 ∅ 𝑇 ) ) ) | 
						
							| 90 |  | noel | ⊢ ¬  𝑊  ∈  ∅ | 
						
							| 91 | 90 | pm2.21i | ⊢ ( 𝑊  ∈  ∅  →  ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) | 
						
							| 92 |  | 0ov | ⊢ ( 𝑆 ∅ 𝑇 )  =  ∅ | 
						
							| 93 | 91 92 | eleq2s | ⊢ ( 𝑊  ∈  ( 𝑆 ∅ 𝑇 )  →  ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) | 
						
							| 94 | 89 93 | biimtrdi | ⊢ ( ¬  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( 𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 )  →  ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) ) | 
						
							| 95 | 94 | adantld | ⊢ ( ¬  ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 ) )  →  ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) ) | 
						
							| 96 | 86 95 | pm2.61i | ⊢ ( ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  ∧  𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 ) )  →  ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) | 
						
							| 97 | 96 | ex | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵 ( 𝐶  ∈  𝑈  ∧  𝐷  ∈  𝑉 )  →  ( 𝑊  ∈  ( 𝑆 ( 𝑋 𝑂 𝑌 ) 𝑇 )  →  ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  ∧  ( 𝑆  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐶  ∧  𝑇  ∈  ⦋ 𝑋  /  𝑥 ⦌ ⦋ 𝑌  /  𝑦 ⦌ 𝐷 ) ) ) ) |