| Step | Hyp | Ref | Expression | 
						
							| 1 |  | elovmporab1.o | ⊢ 𝑂  =  ( 𝑥  ∈  V ,  𝑦  ∈  V  ↦  { 𝑧  ∈  ⦋ 𝑥  /  𝑚 ⦌ 𝑀  ∣  𝜑 } ) | 
						
							| 2 |  | elovmporab1.v | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∈  V ) | 
						
							| 3 | 1 | elmpocl | ⊢ ( 𝑍  ∈  ( 𝑋 𝑂 𝑌 )  →  ( 𝑋  ∈  V  ∧  𝑌  ∈  V ) ) | 
						
							| 4 | 1 | a1i | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  𝑂  =  ( 𝑥  ∈  V ,  𝑦  ∈  V  ↦  { 𝑧  ∈  ⦋ 𝑥  /  𝑚 ⦌ 𝑀  ∣  𝜑 } ) ) | 
						
							| 5 |  | csbeq1 | ⊢ ( 𝑥  =  𝑋  →  ⦋ 𝑥  /  𝑚 ⦌ 𝑀  =  ⦋ 𝑋  /  𝑚 ⦌ 𝑀 ) | 
						
							| 6 | 5 | ad2antrl | ⊢ ( ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  ∧  ( 𝑥  =  𝑋  ∧  𝑦  =  𝑌 ) )  →  ⦋ 𝑥  /  𝑚 ⦌ 𝑀  =  ⦋ 𝑋  /  𝑚 ⦌ 𝑀 ) | 
						
							| 7 |  | sbceq1a | ⊢ ( 𝑦  =  𝑌  →  ( 𝜑  ↔  [ 𝑌  /  𝑦 ] 𝜑 ) ) | 
						
							| 8 |  | sbceq1a | ⊢ ( 𝑥  =  𝑋  →  ( [ 𝑌  /  𝑦 ] 𝜑  ↔  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 ) ) | 
						
							| 9 | 7 8 | sylan9bbr | ⊢ ( ( 𝑥  =  𝑋  ∧  𝑦  =  𝑌 )  →  ( 𝜑  ↔  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 ) ) | 
						
							| 10 | 9 | adantl | ⊢ ( ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  ∧  ( 𝑥  =  𝑋  ∧  𝑦  =  𝑌 ) )  →  ( 𝜑  ↔  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 ) ) | 
						
							| 11 | 6 10 | rabeqbidv | ⊢ ( ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  ∧  ( 𝑥  =  𝑋  ∧  𝑦  =  𝑌 ) )  →  { 𝑧  ∈  ⦋ 𝑥  /  𝑚 ⦌ 𝑀  ∣  𝜑 }  =  { 𝑧  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∣  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 } ) | 
						
							| 12 |  | eqidd | ⊢ ( ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  ∧  𝑥  =  𝑋 )  →  V  =  V ) | 
						
							| 13 |  | simpl | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  𝑋  ∈  V ) | 
						
							| 14 |  | simpr | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  𝑌  ∈  V ) | 
						
							| 15 |  | rabexg | ⊢ ( ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∈  V  →  { 𝑧  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∣  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 }  ∈  V ) | 
						
							| 16 | 2 15 | syl | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  { 𝑧  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∣  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 }  ∈  V ) | 
						
							| 17 |  | nfcv | ⊢ Ⅎ 𝑥 𝑋 | 
						
							| 18 | 17 | nfel1 | ⊢ Ⅎ 𝑥 𝑋  ∈  V | 
						
							| 19 |  | nfcv | ⊢ Ⅎ 𝑥 𝑌 | 
						
							| 20 | 19 | nfel1 | ⊢ Ⅎ 𝑥 𝑌  ∈  V | 
						
							| 21 | 18 20 | nfan | ⊢ Ⅎ 𝑥 ( 𝑋  ∈  V  ∧  𝑌  ∈  V ) | 
						
							| 22 |  | nfcv | ⊢ Ⅎ 𝑦 𝑋 | 
						
							| 23 | 22 | nfel1 | ⊢ Ⅎ 𝑦 𝑋  ∈  V | 
						
							| 24 |  | nfcv | ⊢ Ⅎ 𝑦 𝑌 | 
						
							| 25 | 24 | nfel1 | ⊢ Ⅎ 𝑦 𝑌  ∈  V | 
						
							| 26 | 23 25 | nfan | ⊢ Ⅎ 𝑦 ( 𝑋  ∈  V  ∧  𝑌  ∈  V ) | 
						
							| 27 |  | nfsbc1v | ⊢ Ⅎ 𝑥 [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 | 
						
							| 28 |  | nfcv | ⊢ Ⅎ 𝑥 𝑀 | 
						
							| 29 | 17 28 | nfcsb | ⊢ Ⅎ 𝑥 ⦋ 𝑋  /  𝑚 ⦌ 𝑀 | 
						
							| 30 | 27 29 | nfrab | ⊢ Ⅎ 𝑥 { 𝑧  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∣  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 } | 
						
							| 31 |  | nfsbc1v | ⊢ Ⅎ 𝑦 [ 𝑌  /  𝑦 ] 𝜑 | 
						
							| 32 | 22 31 | nfsbc | ⊢ Ⅎ 𝑦 [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 | 
						
							| 33 |  | nfcv | ⊢ Ⅎ 𝑦 𝑀 | 
						
							| 34 | 22 33 | nfcsb | ⊢ Ⅎ 𝑦 ⦋ 𝑋  /  𝑚 ⦌ 𝑀 | 
						
							| 35 | 32 34 | nfrab | ⊢ Ⅎ 𝑦 { 𝑧  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∣  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 } | 
						
							| 36 | 4 11 12 13 14 16 21 26 22 19 30 35 | ovmpodxf | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  ( 𝑋 𝑂 𝑌 )  =  { 𝑧  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∣  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 } ) | 
						
							| 37 | 36 | eleq2d | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  ( 𝑍  ∈  ( 𝑋 𝑂 𝑌 )  ↔  𝑍  ∈  { 𝑧  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∣  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 } ) ) | 
						
							| 38 |  | df-3an | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V  ∧  𝑍  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀 )  ↔  ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  ∧  𝑍  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀 ) ) | 
						
							| 39 | 38 | simplbi2com | ⊢ ( 𝑍  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  →  ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  ( 𝑋  ∈  V  ∧  𝑌  ∈  V  ∧  𝑍  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀 ) ) ) | 
						
							| 40 |  | elrabi | ⊢ ( 𝑍  ∈  { 𝑧  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∣  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 }  →  𝑍  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀 ) | 
						
							| 41 | 39 40 | syl11 | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  ( 𝑍  ∈  { 𝑧  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀  ∣  [ 𝑋  /  𝑥 ] [ 𝑌  /  𝑦 ] 𝜑 }  →  ( 𝑋  ∈  V  ∧  𝑌  ∈  V  ∧  𝑍  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀 ) ) ) | 
						
							| 42 | 37 41 | sylbid | ⊢ ( ( 𝑋  ∈  V  ∧  𝑌  ∈  V )  →  ( 𝑍  ∈  ( 𝑋 𝑂 𝑌 )  →  ( 𝑋  ∈  V  ∧  𝑌  ∈  V  ∧  𝑍  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀 ) ) ) | 
						
							| 43 | 3 42 | mpcom | ⊢ ( 𝑍  ∈  ( 𝑋 𝑂 𝑌 )  →  ( 𝑋  ∈  V  ∧  𝑌  ∈  V  ∧  𝑍  ∈  ⦋ 𝑋  /  𝑚 ⦌ 𝑀 ) ) |