| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-rab | ⊢ { 𝑦  ∈  𝐴  ∣  𝑦 𝑅 𝑥 }  =  { 𝑦  ∣  ( 𝑦  ∈  𝐴  ∧  𝑦 𝑅 𝑥 ) } | 
						
							| 2 |  | vex | ⊢ 𝑦  ∈  V | 
						
							| 3 |  | vex | ⊢ 𝑥  ∈  V | 
						
							| 4 | 2 3 | breldm | ⊢ ( 𝑦 𝑅 𝑥  →  𝑦  ∈  dom  𝑅 ) | 
						
							| 5 | 4 | adantl | ⊢ ( ( 𝑦  ∈  𝐴  ∧  𝑦 𝑅 𝑥 )  →  𝑦  ∈  dom  𝑅 ) | 
						
							| 6 | 5 | abssi | ⊢ { 𝑦  ∣  ( 𝑦  ∈  𝐴  ∧  𝑦 𝑅 𝑥 ) }  ⊆  dom  𝑅 | 
						
							| 7 | 1 6 | eqsstri | ⊢ { 𝑦  ∈  𝐴  ∣  𝑦 𝑅 𝑥 }  ⊆  dom  𝑅 | 
						
							| 8 |  | dmexg | ⊢ ( 𝑅  ∈  𝑉  →  dom  𝑅  ∈  V ) | 
						
							| 9 |  | ssexg | ⊢ ( ( { 𝑦  ∈  𝐴  ∣  𝑦 𝑅 𝑥 }  ⊆  dom  𝑅  ∧  dom  𝑅  ∈  V )  →  { 𝑦  ∈  𝐴  ∣  𝑦 𝑅 𝑥 }  ∈  V ) | 
						
							| 10 | 7 8 9 | sylancr | ⊢ ( 𝑅  ∈  𝑉  →  { 𝑦  ∈  𝐴  ∣  𝑦 𝑅 𝑥 }  ∈  V ) | 
						
							| 11 | 10 | ralrimivw | ⊢ ( 𝑅  ∈  𝑉  →  ∀ 𝑥  ∈  𝐴 { 𝑦  ∈  𝐴  ∣  𝑦 𝑅 𝑥 }  ∈  V ) | 
						
							| 12 |  | df-se | ⊢ ( 𝑅  Se  𝐴  ↔  ∀ 𝑥  ∈  𝐴 { 𝑦  ∈  𝐴  ∣  𝑦 𝑅 𝑥 }  ∈  V ) | 
						
							| 13 | 11 12 | sylibr | ⊢ ( 𝑅  ∈  𝑉  →  𝑅  Se  𝐴 ) |