| Step | Hyp | Ref | Expression | 
						
							| 0 |  | ctgp | ⊢ TopGrp | 
						
							| 1 |  | vf | ⊢ 𝑓 | 
						
							| 2 |  | cgrp | ⊢ Grp | 
						
							| 3 |  | ctmd | ⊢ TopMnd | 
						
							| 4 | 2 3 | cin | ⊢ ( Grp  ∩  TopMnd ) | 
						
							| 5 |  | ctopn | ⊢ TopOpen | 
						
							| 6 | 1 | cv | ⊢ 𝑓 | 
						
							| 7 | 6 5 | cfv | ⊢ ( TopOpen ‘ 𝑓 ) | 
						
							| 8 |  | vj | ⊢ 𝑗 | 
						
							| 9 |  | cminusg | ⊢ invg | 
						
							| 10 | 6 9 | cfv | ⊢ ( invg ‘ 𝑓 ) | 
						
							| 11 | 8 | cv | ⊢ 𝑗 | 
						
							| 12 |  | ccn | ⊢  Cn | 
						
							| 13 | 11 11 12 | co | ⊢ ( 𝑗  Cn  𝑗 ) | 
						
							| 14 | 10 13 | wcel | ⊢ ( invg ‘ 𝑓 )  ∈  ( 𝑗  Cn  𝑗 ) | 
						
							| 15 | 14 8 7 | wsbc | ⊢ [ ( TopOpen ‘ 𝑓 )  /  𝑗 ] ( invg ‘ 𝑓 )  ∈  ( 𝑗  Cn  𝑗 ) | 
						
							| 16 | 15 1 4 | crab | ⊢ { 𝑓  ∈  ( Grp  ∩  TopMnd )  ∣  [ ( TopOpen ‘ 𝑓 )  /  𝑗 ] ( invg ‘ 𝑓 )  ∈  ( 𝑗  Cn  𝑗 ) } | 
						
							| 17 | 0 16 | wceq | ⊢ TopGrp  =  { 𝑓  ∈  ( Grp  ∩  TopMnd )  ∣  [ ( TopOpen ‘ 𝑓 )  /  𝑗 ] ( invg ‘ 𝑓 )  ∈  ( 𝑗  Cn  𝑗 ) } |