| Step | Hyp | Ref | Expression | 
						
							| 1 |  | resvbas.1 | ⊢ 𝐻  =  ( 𝐺  ↾v  𝐴 ) | 
						
							| 2 |  | resv1r.2 | ⊢  1   =  ( 1r ‘ 𝐺 ) | 
						
							| 3 |  | eqid | ⊢ ( Base ‘ 𝐺 )  =  ( Base ‘ 𝐺 ) | 
						
							| 4 | 1 3 | resvbas | ⊢ ( 𝐴  ∈  𝑉  →  ( Base ‘ 𝐺 )  =  ( Base ‘ 𝐻 ) ) | 
						
							| 5 | 4 | eleq2d | ⊢ ( 𝐴  ∈  𝑉  →  ( 𝑒  ∈  ( Base ‘ 𝐺 )  ↔  𝑒  ∈  ( Base ‘ 𝐻 ) ) ) | 
						
							| 6 |  | eqid | ⊢ ( .r ‘ 𝐺 )  =  ( .r ‘ 𝐺 ) | 
						
							| 7 | 1 6 | resvmulr | ⊢ ( 𝐴  ∈  𝑉  →  ( .r ‘ 𝐺 )  =  ( .r ‘ 𝐻 ) ) | 
						
							| 8 | 7 | oveqd | ⊢ ( 𝐴  ∈  𝑉  →  ( 𝑒 ( .r ‘ 𝐺 ) 𝑥 )  =  ( 𝑒 ( .r ‘ 𝐻 ) 𝑥 ) ) | 
						
							| 9 | 8 | eqeq1d | ⊢ ( 𝐴  ∈  𝑉  →  ( ( 𝑒 ( .r ‘ 𝐺 ) 𝑥 )  =  𝑥  ↔  ( 𝑒 ( .r ‘ 𝐻 ) 𝑥 )  =  𝑥 ) ) | 
						
							| 10 | 7 | oveqd | ⊢ ( 𝐴  ∈  𝑉  →  ( 𝑥 ( .r ‘ 𝐺 ) 𝑒 )  =  ( 𝑥 ( .r ‘ 𝐻 ) 𝑒 ) ) | 
						
							| 11 | 10 | eqeq1d | ⊢ ( 𝐴  ∈  𝑉  →  ( ( 𝑥 ( .r ‘ 𝐺 ) 𝑒 )  =  𝑥  ↔  ( 𝑥 ( .r ‘ 𝐻 ) 𝑒 )  =  𝑥 ) ) | 
						
							| 12 | 9 11 | anbi12d | ⊢ ( 𝐴  ∈  𝑉  →  ( ( ( 𝑒 ( .r ‘ 𝐺 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐺 ) 𝑒 )  =  𝑥 )  ↔  ( ( 𝑒 ( .r ‘ 𝐻 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐻 ) 𝑒 )  =  𝑥 ) ) ) | 
						
							| 13 | 4 12 | raleqbidv | ⊢ ( 𝐴  ∈  𝑉  →  ( ∀ 𝑥  ∈  ( Base ‘ 𝐺 ) ( ( 𝑒 ( .r ‘ 𝐺 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐺 ) 𝑒 )  =  𝑥 )  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐻 ) ( ( 𝑒 ( .r ‘ 𝐻 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐻 ) 𝑒 )  =  𝑥 ) ) ) | 
						
							| 14 | 5 13 | anbi12d | ⊢ ( 𝐴  ∈  𝑉  →  ( ( 𝑒  ∈  ( Base ‘ 𝐺 )  ∧  ∀ 𝑥  ∈  ( Base ‘ 𝐺 ) ( ( 𝑒 ( .r ‘ 𝐺 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐺 ) 𝑒 )  =  𝑥 ) )  ↔  ( 𝑒  ∈  ( Base ‘ 𝐻 )  ∧  ∀ 𝑥  ∈  ( Base ‘ 𝐻 ) ( ( 𝑒 ( .r ‘ 𝐻 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐻 ) 𝑒 )  =  𝑥 ) ) ) ) | 
						
							| 15 | 14 | iotabidv | ⊢ ( 𝐴  ∈  𝑉  →  ( ℩ 𝑒 ( 𝑒  ∈  ( Base ‘ 𝐺 )  ∧  ∀ 𝑥  ∈  ( Base ‘ 𝐺 ) ( ( 𝑒 ( .r ‘ 𝐺 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐺 ) 𝑒 )  =  𝑥 ) ) )  =  ( ℩ 𝑒 ( 𝑒  ∈  ( Base ‘ 𝐻 )  ∧  ∀ 𝑥  ∈  ( Base ‘ 𝐻 ) ( ( 𝑒 ( .r ‘ 𝐻 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐻 ) 𝑒 )  =  𝑥 ) ) ) ) | 
						
							| 16 | 3 6 2 | dfur2 | ⊢  1   =  ( ℩ 𝑒 ( 𝑒  ∈  ( Base ‘ 𝐺 )  ∧  ∀ 𝑥  ∈  ( Base ‘ 𝐺 ) ( ( 𝑒 ( .r ‘ 𝐺 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐺 ) 𝑒 )  =  𝑥 ) ) ) | 
						
							| 17 |  | eqid | ⊢ ( Base ‘ 𝐻 )  =  ( Base ‘ 𝐻 ) | 
						
							| 18 |  | eqid | ⊢ ( .r ‘ 𝐻 )  =  ( .r ‘ 𝐻 ) | 
						
							| 19 |  | eqid | ⊢ ( 1r ‘ 𝐻 )  =  ( 1r ‘ 𝐻 ) | 
						
							| 20 | 17 18 19 | dfur2 | ⊢ ( 1r ‘ 𝐻 )  =  ( ℩ 𝑒 ( 𝑒  ∈  ( Base ‘ 𝐻 )  ∧  ∀ 𝑥  ∈  ( Base ‘ 𝐻 ) ( ( 𝑒 ( .r ‘ 𝐻 ) 𝑥 )  =  𝑥  ∧  ( 𝑥 ( .r ‘ 𝐻 ) 𝑒 )  =  𝑥 ) ) ) | 
						
							| 21 | 15 16 20 | 3eqtr4g | ⊢ ( 𝐴  ∈  𝑉  →   1   =  ( 1r ‘ 𝐻 ) ) |