| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cbvrabcsfw.1 | ⊢ Ⅎ 𝑦 𝐴 | 
						
							| 2 |  | cbvrabcsfw.2 | ⊢ Ⅎ 𝑥 𝐵 | 
						
							| 3 |  | cbvrabcsfw.3 | ⊢ Ⅎ 𝑦 𝜑 | 
						
							| 4 |  | cbvrabcsfw.4 | ⊢ Ⅎ 𝑥 𝜓 | 
						
							| 5 |  | cbvrabcsfw.5 | ⊢ ( 𝑥  =  𝑦  →  𝐴  =  𝐵 ) | 
						
							| 6 |  | cbvrabcsfw.6 | ⊢ ( 𝑥  =  𝑦  →  ( 𝜑  ↔  𝜓 ) ) | 
						
							| 7 |  | nfv | ⊢ Ⅎ 𝑧 ( 𝑥  ∈  𝐴  ∧  𝜑 ) | 
						
							| 8 |  | nfcsb1v | ⊢ Ⅎ 𝑥 ⦋ 𝑧  /  𝑥 ⦌ 𝐴 | 
						
							| 9 | 8 | nfcri | ⊢ Ⅎ 𝑥 𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴 | 
						
							| 10 |  | nfs1v | ⊢ Ⅎ 𝑥 [ 𝑧  /  𝑥 ] 𝜑 | 
						
							| 11 | 9 10 | nfan | ⊢ Ⅎ 𝑥 ( 𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴  ∧  [ 𝑧  /  𝑥 ] 𝜑 ) | 
						
							| 12 |  | id | ⊢ ( 𝑥  =  𝑧  →  𝑥  =  𝑧 ) | 
						
							| 13 |  | csbeq1a | ⊢ ( 𝑥  =  𝑧  →  𝐴  =  ⦋ 𝑧  /  𝑥 ⦌ 𝐴 ) | 
						
							| 14 | 12 13 | eleq12d | ⊢ ( 𝑥  =  𝑧  →  ( 𝑥  ∈  𝐴  ↔  𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴 ) ) | 
						
							| 15 |  | sbequ12 | ⊢ ( 𝑥  =  𝑧  →  ( 𝜑  ↔  [ 𝑧  /  𝑥 ] 𝜑 ) ) | 
						
							| 16 | 14 15 | anbi12d | ⊢ ( 𝑥  =  𝑧  →  ( ( 𝑥  ∈  𝐴  ∧  𝜑 )  ↔  ( 𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴  ∧  [ 𝑧  /  𝑥 ] 𝜑 ) ) ) | 
						
							| 17 | 7 11 16 | cbvabw | ⊢ { 𝑥  ∣  ( 𝑥  ∈  𝐴  ∧  𝜑 ) }  =  { 𝑧  ∣  ( 𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴  ∧  [ 𝑧  /  𝑥 ] 𝜑 ) } | 
						
							| 18 |  | nfcv | ⊢ Ⅎ 𝑦 𝑧 | 
						
							| 19 | 18 1 | nfcsbw | ⊢ Ⅎ 𝑦 ⦋ 𝑧  /  𝑥 ⦌ 𝐴 | 
						
							| 20 | 19 | nfcri | ⊢ Ⅎ 𝑦 𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴 | 
						
							| 21 | 3 | nfsbv | ⊢ Ⅎ 𝑦 [ 𝑧  /  𝑥 ] 𝜑 | 
						
							| 22 | 20 21 | nfan | ⊢ Ⅎ 𝑦 ( 𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴  ∧  [ 𝑧  /  𝑥 ] 𝜑 ) | 
						
							| 23 |  | nfv | ⊢ Ⅎ 𝑧 ( 𝑦  ∈  𝐵  ∧  𝜓 ) | 
						
							| 24 |  | id | ⊢ ( 𝑧  =  𝑦  →  𝑧  =  𝑦 ) | 
						
							| 25 |  | csbeq1 | ⊢ ( 𝑧  =  𝑦  →  ⦋ 𝑧  /  𝑥 ⦌ 𝐴  =  ⦋ 𝑦  /  𝑥 ⦌ 𝐴 ) | 
						
							| 26 |  | vex | ⊢ 𝑦  ∈  V | 
						
							| 27 | 26 2 5 | csbief | ⊢ ⦋ 𝑦  /  𝑥 ⦌ 𝐴  =  𝐵 | 
						
							| 28 | 25 27 | eqtrdi | ⊢ ( 𝑧  =  𝑦  →  ⦋ 𝑧  /  𝑥 ⦌ 𝐴  =  𝐵 ) | 
						
							| 29 | 24 28 | eleq12d | ⊢ ( 𝑧  =  𝑦  →  ( 𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴  ↔  𝑦  ∈  𝐵 ) ) | 
						
							| 30 | 4 6 | sbhypf | ⊢ ( 𝑧  =  𝑦  →  ( [ 𝑧  /  𝑥 ] 𝜑  ↔  𝜓 ) ) | 
						
							| 31 | 29 30 | anbi12d | ⊢ ( 𝑧  =  𝑦  →  ( ( 𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴  ∧  [ 𝑧  /  𝑥 ] 𝜑 )  ↔  ( 𝑦  ∈  𝐵  ∧  𝜓 ) ) ) | 
						
							| 32 | 22 23 31 | cbvabw | ⊢ { 𝑧  ∣  ( 𝑧  ∈  ⦋ 𝑧  /  𝑥 ⦌ 𝐴  ∧  [ 𝑧  /  𝑥 ] 𝜑 ) }  =  { 𝑦  ∣  ( 𝑦  ∈  𝐵  ∧  𝜓 ) } | 
						
							| 33 | 17 32 | eqtri | ⊢ { 𝑥  ∣  ( 𝑥  ∈  𝐴  ∧  𝜑 ) }  =  { 𝑦  ∣  ( 𝑦  ∈  𝐵  ∧  𝜓 ) } | 
						
							| 34 |  | df-rab | ⊢ { 𝑥  ∈  𝐴  ∣  𝜑 }  =  { 𝑥  ∣  ( 𝑥  ∈  𝐴  ∧  𝜑 ) } | 
						
							| 35 |  | df-rab | ⊢ { 𝑦  ∈  𝐵  ∣  𝜓 }  =  { 𝑦  ∣  ( 𝑦  ∈  𝐵  ∧  𝜓 ) } | 
						
							| 36 | 33 34 35 | 3eqtr4i | ⊢ { 𝑥  ∈  𝐴  ∣  𝜑 }  =  { 𝑦  ∈  𝐵  ∣  𝜓 } |