| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mgpress.1 | ⊢ 𝑆  =  ( 𝑅  ↾s  𝐴 ) | 
						
							| 2 |  | mgpress.2 | ⊢ 𝑀  =  ( mulGrp ‘ 𝑅 ) | 
						
							| 3 |  | simpr | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( Base ‘ 𝑅 )  ⊆  𝐴 ) | 
						
							| 4 | 2 | fvexi | ⊢ 𝑀  ∈  V | 
						
							| 5 | 4 | a1i | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  𝑀  ∈  V ) | 
						
							| 6 |  | simplr | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  𝐴  ∈  𝑊 ) | 
						
							| 7 |  | eqid | ⊢ ( 𝑀  ↾s  𝐴 )  =  ( 𝑀  ↾s  𝐴 ) | 
						
							| 8 |  | eqid | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑅 ) | 
						
							| 9 | 2 8 | mgpbas | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑀 ) | 
						
							| 10 | 7 9 | ressid2 | ⊢ ( ( ( Base ‘ 𝑅 )  ⊆  𝐴  ∧  𝑀  ∈  V  ∧  𝐴  ∈  𝑊 )  →  ( 𝑀  ↾s  𝐴 )  =  𝑀 ) | 
						
							| 11 | 3 5 6 10 | syl3anc | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( 𝑀  ↾s  𝐴 )  =  𝑀 ) | 
						
							| 12 |  | simpll | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  𝑅  ∈  𝑉 ) | 
						
							| 13 | 1 8 | ressid2 | ⊢ ( ( ( Base ‘ 𝑅 )  ⊆  𝐴  ∧  𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  →  𝑆  =  𝑅 ) | 
						
							| 14 | 3 12 6 13 | syl3anc | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  𝑆  =  𝑅 ) | 
						
							| 15 | 14 | fveq2d | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( mulGrp ‘ 𝑆 )  =  ( mulGrp ‘ 𝑅 ) ) | 
						
							| 16 | 2 11 15 | 3eqtr4a | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( 𝑀  ↾s  𝐴 )  =  ( mulGrp ‘ 𝑆 ) ) | 
						
							| 17 |  | eqid | ⊢ ( .r ‘ 𝑅 )  =  ( .r ‘ 𝑅 ) | 
						
							| 18 | 2 17 | mgpval | ⊢ 𝑀  =  ( 𝑅  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 ) | 
						
							| 19 | 18 | oveq1i | ⊢ ( 𝑀  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 )  =  ( ( 𝑅  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 )  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 ) | 
						
							| 20 |  | simpr | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 ) | 
						
							| 21 | 4 | a1i | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  𝑀  ∈  V ) | 
						
							| 22 |  | simplr | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  𝐴  ∈  𝑊 ) | 
						
							| 23 | 7 9 | ressval2 | ⊢ ( ( ¬  ( Base ‘ 𝑅 )  ⊆  𝐴  ∧  𝑀  ∈  V  ∧  𝐴  ∈  𝑊 )  →  ( 𝑀  ↾s  𝐴 )  =  ( 𝑀  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 ) ) | 
						
							| 24 | 20 21 22 23 | syl3anc | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( 𝑀  ↾s  𝐴 )  =  ( 𝑀  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 ) ) | 
						
							| 25 |  | eqid | ⊢ ( mulGrp ‘ 𝑆 )  =  ( mulGrp ‘ 𝑆 ) | 
						
							| 26 |  | eqid | ⊢ ( .r ‘ 𝑆 )  =  ( .r ‘ 𝑆 ) | 
						
							| 27 | 25 26 | mgpval | ⊢ ( mulGrp ‘ 𝑆 )  =  ( 𝑆  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑆 ) 〉 ) | 
						
							| 28 |  | simpll | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  𝑅  ∈  𝑉 ) | 
						
							| 29 | 1 8 | ressval2 | ⊢ ( ( ¬  ( Base ‘ 𝑅 )  ⊆  𝐴  ∧  𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  →  𝑆  =  ( 𝑅  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 ) ) | 
						
							| 30 | 20 28 22 29 | syl3anc | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  𝑆  =  ( 𝑅  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 ) ) | 
						
							| 31 | 1 17 | ressmulr | ⊢ ( 𝐴  ∈  𝑊  →  ( .r ‘ 𝑅 )  =  ( .r ‘ 𝑆 ) ) | 
						
							| 32 | 31 | eqcomd | ⊢ ( 𝐴  ∈  𝑊  →  ( .r ‘ 𝑆 )  =  ( .r ‘ 𝑅 ) ) | 
						
							| 33 | 32 | ad2antlr | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( .r ‘ 𝑆 )  =  ( .r ‘ 𝑅 ) ) | 
						
							| 34 | 33 | opeq2d | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑆 ) 〉  =  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 ) | 
						
							| 35 | 30 34 | oveq12d | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( 𝑆  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑆 ) 〉 )  =  ( ( 𝑅  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 )  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 ) ) | 
						
							| 36 | 27 35 | eqtrid | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( mulGrp ‘ 𝑆 )  =  ( ( 𝑅  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 )  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 ) ) | 
						
							| 37 |  | basendxnplusgndx | ⊢ ( Base ‘ ndx )  ≠  ( +g ‘ ndx ) | 
						
							| 38 | 37 | necomi | ⊢ ( +g ‘ ndx )  ≠  ( Base ‘ ndx ) | 
						
							| 39 |  | fvex | ⊢ ( .r ‘ 𝑅 )  ∈  V | 
						
							| 40 |  | fvex | ⊢ ( Base ‘ 𝑅 )  ∈  V | 
						
							| 41 | 40 | inex2 | ⊢ ( 𝐴  ∩  ( Base ‘ 𝑅 ) )  ∈  V | 
						
							| 42 |  | fvex | ⊢ ( +g ‘ ndx )  ∈  V | 
						
							| 43 |  | fvex | ⊢ ( Base ‘ ndx )  ∈  V | 
						
							| 44 | 42 43 | setscom | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  ( +g ‘ ndx )  ≠  ( Base ‘ ndx ) )  ∧  ( ( .r ‘ 𝑅 )  ∈  V  ∧  ( 𝐴  ∩  ( Base ‘ 𝑅 ) )  ∈  V ) )  →  ( ( 𝑅  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 )  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 )  =  ( ( 𝑅  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 )  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 ) ) | 
						
							| 45 | 39 41 44 | mpanr12 | ⊢ ( ( 𝑅  ∈  𝑉  ∧  ( +g ‘ ndx )  ≠  ( Base ‘ ndx ) )  →  ( ( 𝑅  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 )  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 )  =  ( ( 𝑅  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 )  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 ) ) | 
						
							| 46 | 28 38 45 | sylancl | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( ( 𝑅  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 )  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 )  =  ( ( 𝑅  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 )  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 ) ) | 
						
							| 47 | 36 46 | eqtr4d | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( mulGrp ‘ 𝑆 )  =  ( ( 𝑅  sSet  〈 ( +g ‘ ndx ) ,  ( .r ‘ 𝑅 ) 〉 )  sSet  〈 ( Base ‘ ndx ) ,  ( 𝐴  ∩  ( Base ‘ 𝑅 ) ) 〉 ) ) | 
						
							| 48 | 19 24 47 | 3eqtr4a | ⊢ ( ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  ∧  ¬  ( Base ‘ 𝑅 )  ⊆  𝐴 )  →  ( 𝑀  ↾s  𝐴 )  =  ( mulGrp ‘ 𝑆 ) ) | 
						
							| 49 | 16 48 | pm2.61dan | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝐴  ∈  𝑊 )  →  ( 𝑀  ↾s  𝐴 )  =  ( mulGrp ‘ 𝑆 ) ) |