| Step | Hyp | Ref | Expression | 
						
							| 1 |  | elex | ⊢ ( 𝐴  ∈  𝑉  →  𝐴  ∈  V ) | 
						
							| 2 |  | grothtsk | ⊢ ∪  Tarski  =  V | 
						
							| 3 | 1 2 | eleqtrrdi | ⊢ ( 𝐴  ∈  𝑉  →  𝐴  ∈  ∪  Tarski ) | 
						
							| 4 |  | eluni2 | ⊢ ( 𝐴  ∈  ∪  Tarski  ↔  ∃ 𝑥  ∈  Tarski 𝐴  ∈  𝑥 ) | 
						
							| 5 | 3 4 | sylib | ⊢ ( 𝐴  ∈  𝑉  →  ∃ 𝑥  ∈  Tarski 𝐴  ∈  𝑥 ) | 
						
							| 6 |  | intexrab | ⊢ ( ∃ 𝑥  ∈  Tarski 𝐴  ∈  𝑥  ↔  ∩  { 𝑥  ∈  Tarski  ∣  𝐴  ∈  𝑥 }  ∈  V ) | 
						
							| 7 | 5 6 | sylib | ⊢ ( 𝐴  ∈  𝑉  →  ∩  { 𝑥  ∈  Tarski  ∣  𝐴  ∈  𝑥 }  ∈  V ) | 
						
							| 8 |  | eleq1 | ⊢ ( 𝑦  =  𝐴  →  ( 𝑦  ∈  𝑥  ↔  𝐴  ∈  𝑥 ) ) | 
						
							| 9 | 8 | rabbidv | ⊢ ( 𝑦  =  𝐴  →  { 𝑥  ∈  Tarski  ∣  𝑦  ∈  𝑥 }  =  { 𝑥  ∈  Tarski  ∣  𝐴  ∈  𝑥 } ) | 
						
							| 10 | 9 | inteqd | ⊢ ( 𝑦  =  𝐴  →  ∩  { 𝑥  ∈  Tarski  ∣  𝑦  ∈  𝑥 }  =  ∩  { 𝑥  ∈  Tarski  ∣  𝐴  ∈  𝑥 } ) | 
						
							| 11 |  | df-tskm | ⊢ tarskiMap  =  ( 𝑦  ∈  V  ↦  ∩  { 𝑥  ∈  Tarski  ∣  𝑦  ∈  𝑥 } ) | 
						
							| 12 | 10 11 | fvmptg | ⊢ ( ( 𝐴  ∈  V  ∧  ∩  { 𝑥  ∈  Tarski  ∣  𝐴  ∈  𝑥 }  ∈  V )  →  ( tarskiMap ‘ 𝐴 )  =  ∩  { 𝑥  ∈  Tarski  ∣  𝐴  ∈  𝑥 } ) | 
						
							| 13 | 1 7 12 | syl2anc | ⊢ ( 𝐴  ∈  𝑉  →  ( tarskiMap ‘ 𝐴 )  =  ∩  { 𝑥  ∈  Tarski  ∣  𝐴  ∈  𝑥 } ) |