| Step | Hyp | Ref | Expression | 
						
							| 1 |  | prdsmgp.y | ⊢ 𝑌  =  ( 𝑆 Xs 𝑅 ) | 
						
							| 2 |  | prdsmgp.m | ⊢ 𝑀  =  ( mulGrp ‘ 𝑌 ) | 
						
							| 3 |  | prdsmgp.z | ⊢ 𝑍  =  ( 𝑆 Xs ( mulGrp  ∘  𝑅 ) ) | 
						
							| 4 |  | prdsmgp.i | ⊢ ( 𝜑  →  𝐼  ∈  𝑉 ) | 
						
							| 5 |  | prdsmgp.s | ⊢ ( 𝜑  →  𝑆  ∈  𝑊 ) | 
						
							| 6 |  | prdsmgp.r | ⊢ ( 𝜑  →  𝑅  Fn  𝐼 ) | 
						
							| 7 |  | eqid | ⊢ ( mulGrp ‘ ( 𝑅 ‘ 𝑥 ) )  =  ( mulGrp ‘ ( 𝑅 ‘ 𝑥 ) ) | 
						
							| 8 |  | eqid | ⊢ ( Base ‘ ( 𝑅 ‘ 𝑥 ) )  =  ( Base ‘ ( 𝑅 ‘ 𝑥 ) ) | 
						
							| 9 | 7 8 | mgpbas | ⊢ ( Base ‘ ( 𝑅 ‘ 𝑥 ) )  =  ( Base ‘ ( mulGrp ‘ ( 𝑅 ‘ 𝑥 ) ) ) | 
						
							| 10 |  | fvco2 | ⊢ ( ( 𝑅  Fn  𝐼  ∧  𝑥  ∈  𝐼 )  →  ( ( mulGrp  ∘  𝑅 ) ‘ 𝑥 )  =  ( mulGrp ‘ ( 𝑅 ‘ 𝑥 ) ) ) | 
						
							| 11 | 6 10 | sylan | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐼 )  →  ( ( mulGrp  ∘  𝑅 ) ‘ 𝑥 )  =  ( mulGrp ‘ ( 𝑅 ‘ 𝑥 ) ) ) | 
						
							| 12 | 11 | eqcomd | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐼 )  →  ( mulGrp ‘ ( 𝑅 ‘ 𝑥 ) )  =  ( ( mulGrp  ∘  𝑅 ) ‘ 𝑥 ) ) | 
						
							| 13 | 12 | fveq2d | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐼 )  →  ( Base ‘ ( mulGrp ‘ ( 𝑅 ‘ 𝑥 ) ) )  =  ( Base ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑥 ) ) ) | 
						
							| 14 | 9 13 | eqtrid | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐼 )  →  ( Base ‘ ( 𝑅 ‘ 𝑥 ) )  =  ( Base ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑥 ) ) ) | 
						
							| 15 | 14 | ixpeq2dva | ⊢ ( 𝜑  →  X 𝑥  ∈  𝐼 ( Base ‘ ( 𝑅 ‘ 𝑥 ) )  =  X 𝑥  ∈  𝐼 ( Base ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑥 ) ) ) | 
						
							| 16 |  | eqid | ⊢ ( Base ‘ 𝑌 )  =  ( Base ‘ 𝑌 ) | 
						
							| 17 | 2 16 | mgpbas | ⊢ ( Base ‘ 𝑌 )  =  ( Base ‘ 𝑀 ) | 
						
							| 18 | 17 | eqcomi | ⊢ ( Base ‘ 𝑀 )  =  ( Base ‘ 𝑌 ) | 
						
							| 19 | 1 18 5 4 6 | prdsbas2 | ⊢ ( 𝜑  →  ( Base ‘ 𝑀 )  =  X 𝑥  ∈  𝐼 ( Base ‘ ( 𝑅 ‘ 𝑥 ) ) ) | 
						
							| 20 |  | eqid | ⊢ ( Base ‘ 𝑍 )  =  ( Base ‘ 𝑍 ) | 
						
							| 21 |  | fnmgp | ⊢ mulGrp  Fn  V | 
						
							| 22 |  | ssv | ⊢ ran  𝑅  ⊆  V | 
						
							| 23 | 22 | a1i | ⊢ ( 𝜑  →  ran  𝑅  ⊆  V ) | 
						
							| 24 |  | fnco | ⊢ ( ( mulGrp  Fn  V  ∧  𝑅  Fn  𝐼  ∧  ran  𝑅  ⊆  V )  →  ( mulGrp  ∘  𝑅 )  Fn  𝐼 ) | 
						
							| 25 | 21 6 23 24 | mp3an2i | ⊢ ( 𝜑  →  ( mulGrp  ∘  𝑅 )  Fn  𝐼 ) | 
						
							| 26 | 3 20 5 4 25 | prdsbas2 | ⊢ ( 𝜑  →  ( Base ‘ 𝑍 )  =  X 𝑥  ∈  𝐼 ( Base ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑥 ) ) ) | 
						
							| 27 | 15 19 26 | 3eqtr4d | ⊢ ( 𝜑  →  ( Base ‘ 𝑀 )  =  ( Base ‘ 𝑍 ) ) | 
						
							| 28 |  | eqid | ⊢ ( .r ‘ 𝑌 )  =  ( .r ‘ 𝑌 ) | 
						
							| 29 | 2 28 | mgpplusg | ⊢ ( .r ‘ 𝑌 )  =  ( +g ‘ 𝑀 ) | 
						
							| 30 |  | eqid | ⊢ ( mulGrp ‘ ( 𝑅 ‘ 𝑧 ) )  =  ( mulGrp ‘ ( 𝑅 ‘ 𝑧 ) ) | 
						
							| 31 |  | eqid | ⊢ ( .r ‘ ( 𝑅 ‘ 𝑧 ) )  =  ( .r ‘ ( 𝑅 ‘ 𝑧 ) ) | 
						
							| 32 | 30 31 | mgpplusg | ⊢ ( .r ‘ ( 𝑅 ‘ 𝑧 ) )  =  ( +g ‘ ( mulGrp ‘ ( 𝑅 ‘ 𝑧 ) ) ) | 
						
							| 33 |  | fvco2 | ⊢ ( ( 𝑅  Fn  𝐼  ∧  𝑧  ∈  𝐼 )  →  ( ( mulGrp  ∘  𝑅 ) ‘ 𝑧 )  =  ( mulGrp ‘ ( 𝑅 ‘ 𝑧 ) ) ) | 
						
							| 34 | 6 33 | sylan | ⊢ ( ( 𝜑  ∧  𝑧  ∈  𝐼 )  →  ( ( mulGrp  ∘  𝑅 ) ‘ 𝑧 )  =  ( mulGrp ‘ ( 𝑅 ‘ 𝑧 ) ) ) | 
						
							| 35 | 34 | eqcomd | ⊢ ( ( 𝜑  ∧  𝑧  ∈  𝐼 )  →  ( mulGrp ‘ ( 𝑅 ‘ 𝑧 ) )  =  ( ( mulGrp  ∘  𝑅 ) ‘ 𝑧 ) ) | 
						
							| 36 | 35 | fveq2d | ⊢ ( ( 𝜑  ∧  𝑧  ∈  𝐼 )  →  ( +g ‘ ( mulGrp ‘ ( 𝑅 ‘ 𝑧 ) ) )  =  ( +g ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑧 ) ) ) | 
						
							| 37 | 32 36 | eqtrid | ⊢ ( ( 𝜑  ∧  𝑧  ∈  𝐼 )  →  ( .r ‘ ( 𝑅 ‘ 𝑧 ) )  =  ( +g ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑧 ) ) ) | 
						
							| 38 | 37 | oveqd | ⊢ ( ( 𝜑  ∧  𝑧  ∈  𝐼 )  →  ( ( 𝑥 ‘ 𝑧 ) ( .r ‘ ( 𝑅 ‘ 𝑧 ) ) ( 𝑦 ‘ 𝑧 ) )  =  ( ( 𝑥 ‘ 𝑧 ) ( +g ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑧 ) ) ( 𝑦 ‘ 𝑧 ) ) ) | 
						
							| 39 | 38 | mpteq2dva | ⊢ ( 𝜑  →  ( 𝑧  ∈  𝐼  ↦  ( ( 𝑥 ‘ 𝑧 ) ( .r ‘ ( 𝑅 ‘ 𝑧 ) ) ( 𝑦 ‘ 𝑧 ) ) )  =  ( 𝑧  ∈  𝐼  ↦  ( ( 𝑥 ‘ 𝑧 ) ( +g ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑧 ) ) ( 𝑦 ‘ 𝑧 ) ) ) ) | 
						
							| 40 | 27 27 39 | mpoeq123dv | ⊢ ( 𝜑  →  ( 𝑥  ∈  ( Base ‘ 𝑀 ) ,  𝑦  ∈  ( Base ‘ 𝑀 )  ↦  ( 𝑧  ∈  𝐼  ↦  ( ( 𝑥 ‘ 𝑧 ) ( .r ‘ ( 𝑅 ‘ 𝑧 ) ) ( 𝑦 ‘ 𝑧 ) ) ) )  =  ( 𝑥  ∈  ( Base ‘ 𝑍 ) ,  𝑦  ∈  ( Base ‘ 𝑍 )  ↦  ( 𝑧  ∈  𝐼  ↦  ( ( 𝑥 ‘ 𝑧 ) ( +g ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑧 ) ) ( 𝑦 ‘ 𝑧 ) ) ) ) ) | 
						
							| 41 |  | fnex | ⊢ ( ( 𝑅  Fn  𝐼  ∧  𝐼  ∈  𝑉 )  →  𝑅  ∈  V ) | 
						
							| 42 | 6 4 41 | syl2anc | ⊢ ( 𝜑  →  𝑅  ∈  V ) | 
						
							| 43 | 6 | fndmd | ⊢ ( 𝜑  →  dom  𝑅  =  𝐼 ) | 
						
							| 44 | 1 5 42 18 43 28 | prdsmulr | ⊢ ( 𝜑  →  ( .r ‘ 𝑌 )  =  ( 𝑥  ∈  ( Base ‘ 𝑀 ) ,  𝑦  ∈  ( Base ‘ 𝑀 )  ↦  ( 𝑧  ∈  𝐼  ↦  ( ( 𝑥 ‘ 𝑧 ) ( .r ‘ ( 𝑅 ‘ 𝑧 ) ) ( 𝑦 ‘ 𝑧 ) ) ) ) ) | 
						
							| 45 |  | fnex | ⊢ ( ( ( mulGrp  ∘  𝑅 )  Fn  𝐼  ∧  𝐼  ∈  𝑉 )  →  ( mulGrp  ∘  𝑅 )  ∈  V ) | 
						
							| 46 | 25 4 45 | syl2anc | ⊢ ( 𝜑  →  ( mulGrp  ∘  𝑅 )  ∈  V ) | 
						
							| 47 | 25 | fndmd | ⊢ ( 𝜑  →  dom  ( mulGrp  ∘  𝑅 )  =  𝐼 ) | 
						
							| 48 |  | eqid | ⊢ ( +g ‘ 𝑍 )  =  ( +g ‘ 𝑍 ) | 
						
							| 49 | 3 5 46 20 47 48 | prdsplusg | ⊢ ( 𝜑  →  ( +g ‘ 𝑍 )  =  ( 𝑥  ∈  ( Base ‘ 𝑍 ) ,  𝑦  ∈  ( Base ‘ 𝑍 )  ↦  ( 𝑧  ∈  𝐼  ↦  ( ( 𝑥 ‘ 𝑧 ) ( +g ‘ ( ( mulGrp  ∘  𝑅 ) ‘ 𝑧 ) ) ( 𝑦 ‘ 𝑧 ) ) ) ) ) | 
						
							| 50 | 40 44 49 | 3eqtr4d | ⊢ ( 𝜑  →  ( .r ‘ 𝑌 )  =  ( +g ‘ 𝑍 ) ) | 
						
							| 51 | 29 50 | eqtr3id | ⊢ ( 𝜑  →  ( +g ‘ 𝑀 )  =  ( +g ‘ 𝑍 ) ) | 
						
							| 52 | 27 51 | jca | ⊢ ( 𝜑  →  ( ( Base ‘ 𝑀 )  =  ( Base ‘ 𝑍 )  ∧  ( +g ‘ 𝑀 )  =  ( +g ‘ 𝑍 ) ) ) |