| Step | Hyp | Ref | Expression | 
						
							| 0 |  | cgn | ⊢ inv | 
						
							| 1 |  | vg | ⊢ 𝑔 | 
						
							| 2 |  | cgr | ⊢ GrpOp | 
						
							| 3 |  | vx | ⊢ 𝑥 | 
						
							| 4 | 1 | cv | ⊢ 𝑔 | 
						
							| 5 | 4 | crn | ⊢ ran  𝑔 | 
						
							| 6 |  | vz | ⊢ 𝑧 | 
						
							| 7 | 6 | cv | ⊢ 𝑧 | 
						
							| 8 | 3 | cv | ⊢ 𝑥 | 
						
							| 9 | 7 8 4 | co | ⊢ ( 𝑧 𝑔 𝑥 ) | 
						
							| 10 |  | cgi | ⊢ GId | 
						
							| 11 | 4 10 | cfv | ⊢ ( GId ‘ 𝑔 ) | 
						
							| 12 | 9 11 | wceq | ⊢ ( 𝑧 𝑔 𝑥 )  =  ( GId ‘ 𝑔 ) | 
						
							| 13 | 12 6 5 | crio | ⊢ ( ℩ 𝑧  ∈  ran  𝑔 ( 𝑧 𝑔 𝑥 )  =  ( GId ‘ 𝑔 ) ) | 
						
							| 14 | 3 5 13 | cmpt | ⊢ ( 𝑥  ∈  ran  𝑔  ↦  ( ℩ 𝑧  ∈  ran  𝑔 ( 𝑧 𝑔 𝑥 )  =  ( GId ‘ 𝑔 ) ) ) | 
						
							| 15 | 1 2 14 | cmpt | ⊢ ( 𝑔  ∈  GrpOp  ↦  ( 𝑥  ∈  ran  𝑔  ↦  ( ℩ 𝑧  ∈  ran  𝑔 ( 𝑧 𝑔 𝑥 )  =  ( GId ‘ 𝑔 ) ) ) ) | 
						
							| 16 | 0 15 | wceq | ⊢ inv  =  ( 𝑔  ∈  GrpOp  ↦  ( 𝑥  ∈  ran  𝑔  ↦  ( ℩ 𝑧  ∈  ran  𝑔 ( 𝑧 𝑔 𝑥 )  =  ( GId ‘ 𝑔 ) ) ) ) |