| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							dprdsplit.2 | 
							⊢ ( 𝜑  →  𝑆 : 𝐼 ⟶ ( SubGrp ‘ 𝐺 ) )  | 
						
						
							| 2 | 
							
								
							 | 
							dprdsplit.i | 
							⊢ ( 𝜑  →  ( 𝐶  ∩  𝐷 )  =  ∅ )  | 
						
						
							| 3 | 
							
								
							 | 
							dprdsplit.u | 
							⊢ ( 𝜑  →  𝐼  =  ( 𝐶  ∪  𝐷 ) )  | 
						
						
							| 4 | 
							
								
							 | 
							dmdprdsplit.z | 
							⊢ 𝑍  =  ( Cntz ‘ 𝐺 )  | 
						
						
							| 5 | 
							
								
							 | 
							dmdprdsplit.0 | 
							⊢  0   =  ( 0g ‘ 𝐺 )  | 
						
						
							| 6 | 
							
								
							 | 
							dmdprdsplit2.1 | 
							⊢ ( 𝜑  →  𝐺 dom   DProd  ( 𝑆  ↾  𝐶 ) )  | 
						
						
							| 7 | 
							
								
							 | 
							dmdprdsplit2.2 | 
							⊢ ( 𝜑  →  𝐺 dom   DProd  ( 𝑆  ↾  𝐷 ) )  | 
						
						
							| 8 | 
							
								
							 | 
							dmdprdsplit2.3 | 
							⊢ ( 𝜑  →  ( 𝐺  DProd  ( 𝑆  ↾  𝐶 ) )  ⊆  ( 𝑍 ‘ ( 𝐺  DProd  ( 𝑆  ↾  𝐷 ) ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							dmdprdsplit2.4 | 
							⊢ ( 𝜑  →  ( ( 𝐺  DProd  ( 𝑆  ↾  𝐶 ) )  ∩  ( 𝐺  DProd  ( 𝑆  ↾  𝐷 ) ) )  =  {  0  } )  | 
						
						
							| 10 | 
							
								
							 | 
							eqid | 
							⊢ ( mrCls ‘ ( SubGrp ‘ 𝐺 ) )  =  ( mrCls ‘ ( SubGrp ‘ 𝐺 ) )  | 
						
						
							| 11 | 
							
								
							 | 
							dprdgrp | 
							⊢ ( 𝐺 dom   DProd  ( 𝑆  ↾  𝐶 )  →  𝐺  ∈  Grp )  | 
						
						
							| 12 | 
							
								6 11
							 | 
							syl | 
							⊢ ( 𝜑  →  𝐺  ∈  Grp )  | 
						
						
							| 13 | 
							
								
							 | 
							ssun1 | 
							⊢ 𝐶  ⊆  ( 𝐶  ∪  𝐷 )  | 
						
						
							| 14 | 
							
								13 3
							 | 
							sseqtrrid | 
							⊢ ( 𝜑  →  𝐶  ⊆  𝐼 )  | 
						
						
							| 15 | 
							
								1 14
							 | 
							fssresd | 
							⊢ ( 𝜑  →  ( 𝑆  ↾  𝐶 ) : 𝐶 ⟶ ( SubGrp ‘ 𝐺 ) )  | 
						
						
							| 16 | 
							
								15
							 | 
							fdmd | 
							⊢ ( 𝜑  →  dom  ( 𝑆  ↾  𝐶 )  =  𝐶 )  | 
						
						
							| 17 | 
							
								6 16
							 | 
							dprddomcld | 
							⊢ ( 𝜑  →  𝐶  ∈  V )  | 
						
						
							| 18 | 
							
								
							 | 
							ssun2 | 
							⊢ 𝐷  ⊆  ( 𝐶  ∪  𝐷 )  | 
						
						
							| 19 | 
							
								18 3
							 | 
							sseqtrrid | 
							⊢ ( 𝜑  →  𝐷  ⊆  𝐼 )  | 
						
						
							| 20 | 
							
								1 19
							 | 
							fssresd | 
							⊢ ( 𝜑  →  ( 𝑆  ↾  𝐷 ) : 𝐷 ⟶ ( SubGrp ‘ 𝐺 ) )  | 
						
						
							| 21 | 
							
								20
							 | 
							fdmd | 
							⊢ ( 𝜑  →  dom  ( 𝑆  ↾  𝐷 )  =  𝐷 )  | 
						
						
							| 22 | 
							
								7 21
							 | 
							dprddomcld | 
							⊢ ( 𝜑  →  𝐷  ∈  V )  | 
						
						
							| 23 | 
							
								
							 | 
							unexg | 
							⊢ ( ( 𝐶  ∈  V  ∧  𝐷  ∈  V )  →  ( 𝐶  ∪  𝐷 )  ∈  V )  | 
						
						
							| 24 | 
							
								17 22 23
							 | 
							syl2anc | 
							⊢ ( 𝜑  →  ( 𝐶  ∪  𝐷 )  ∈  V )  | 
						
						
							| 25 | 
							
								3 24
							 | 
							eqeltrd | 
							⊢ ( 𝜑  →  𝐼  ∈  V )  | 
						
						
							| 26 | 
							
								3
							 | 
							eleq2d | 
							⊢ ( 𝜑  →  ( 𝑥  ∈  𝐼  ↔  𝑥  ∈  ( 𝐶  ∪  𝐷 ) ) )  | 
						
						
							| 27 | 
							
								
							 | 
							elun | 
							⊢ ( 𝑥  ∈  ( 𝐶  ∪  𝐷 )  ↔  ( 𝑥  ∈  𝐶  ∨  𝑥  ∈  𝐷 ) )  | 
						
						
							| 28 | 
							
								26 27
							 | 
							bitrdi | 
							⊢ ( 𝜑  →  ( 𝑥  ∈  𝐼  ↔  ( 𝑥  ∈  𝐶  ∨  𝑥  ∈  𝐷 ) ) )  | 
						
						
							| 29 | 
							
								1 2 3 4 5 6 7 8 9 10
							 | 
							dmdprdsplit2lem | 
							⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐶 )  →  ( ( 𝑦  ∈  𝐼  →  ( 𝑥  ≠  𝑦  →  ( 𝑆 ‘ 𝑥 )  ⊆  ( 𝑍 ‘ ( 𝑆 ‘ 𝑦 ) ) ) )  ∧  ( ( 𝑆 ‘ 𝑥 )  ∩  ( ( mrCls ‘ ( SubGrp ‘ 𝐺 ) ) ‘ ∪  ( 𝑆  “  ( 𝐼  ∖  { 𝑥 } ) ) ) )  ⊆  {  0  } ) )  | 
						
						
							| 30 | 
							
								
							 | 
							incom | 
							⊢ ( 𝐶  ∩  𝐷 )  =  ( 𝐷  ∩  𝐶 )  | 
						
						
							| 31 | 
							
								30 2
							 | 
							eqtr3id | 
							⊢ ( 𝜑  →  ( 𝐷  ∩  𝐶 )  =  ∅ )  | 
						
						
							| 32 | 
							
								
							 | 
							uncom | 
							⊢ ( 𝐶  ∪  𝐷 )  =  ( 𝐷  ∪  𝐶 )  | 
						
						
							| 33 | 
							
								3 32
							 | 
							eqtrdi | 
							⊢ ( 𝜑  →  𝐼  =  ( 𝐷  ∪  𝐶 ) )  | 
						
						
							| 34 | 
							
								
							 | 
							dprdsubg | 
							⊢ ( 𝐺 dom   DProd  ( 𝑆  ↾  𝐶 )  →  ( 𝐺  DProd  ( 𝑆  ↾  𝐶 ) )  ∈  ( SubGrp ‘ 𝐺 ) )  | 
						
						
							| 35 | 
							
								6 34
							 | 
							syl | 
							⊢ ( 𝜑  →  ( 𝐺  DProd  ( 𝑆  ↾  𝐶 ) )  ∈  ( SubGrp ‘ 𝐺 ) )  | 
						
						
							| 36 | 
							
								
							 | 
							dprdsubg | 
							⊢ ( 𝐺 dom   DProd  ( 𝑆  ↾  𝐷 )  →  ( 𝐺  DProd  ( 𝑆  ↾  𝐷 ) )  ∈  ( SubGrp ‘ 𝐺 ) )  | 
						
						
							| 37 | 
							
								7 36
							 | 
							syl | 
							⊢ ( 𝜑  →  ( 𝐺  DProd  ( 𝑆  ↾  𝐷 ) )  ∈  ( SubGrp ‘ 𝐺 ) )  | 
						
						
							| 38 | 
							
								4 35 37 8
							 | 
							cntzrecd | 
							⊢ ( 𝜑  →  ( 𝐺  DProd  ( 𝑆  ↾  𝐷 ) )  ⊆  ( 𝑍 ‘ ( 𝐺  DProd  ( 𝑆  ↾  𝐶 ) ) ) )  | 
						
						
							| 39 | 
							
								
							 | 
							incom | 
							⊢ ( ( 𝐺  DProd  ( 𝑆  ↾  𝐶 ) )  ∩  ( 𝐺  DProd  ( 𝑆  ↾  𝐷 ) ) )  =  ( ( 𝐺  DProd  ( 𝑆  ↾  𝐷 ) )  ∩  ( 𝐺  DProd  ( 𝑆  ↾  𝐶 ) ) )  | 
						
						
							| 40 | 
							
								39 9
							 | 
							eqtr3id | 
							⊢ ( 𝜑  →  ( ( 𝐺  DProd  ( 𝑆  ↾  𝐷 ) )  ∩  ( 𝐺  DProd  ( 𝑆  ↾  𝐶 ) ) )  =  {  0  } )  | 
						
						
							| 41 | 
							
								1 31 33 4 5 7 6 38 40 10
							 | 
							dmdprdsplit2lem | 
							⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐷 )  →  ( ( 𝑦  ∈  𝐼  →  ( 𝑥  ≠  𝑦  →  ( 𝑆 ‘ 𝑥 )  ⊆  ( 𝑍 ‘ ( 𝑆 ‘ 𝑦 ) ) ) )  ∧  ( ( 𝑆 ‘ 𝑥 )  ∩  ( ( mrCls ‘ ( SubGrp ‘ 𝐺 ) ) ‘ ∪  ( 𝑆  “  ( 𝐼  ∖  { 𝑥 } ) ) ) )  ⊆  {  0  } ) )  | 
						
						
							| 42 | 
							
								29 41
							 | 
							jaodan | 
							⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐶  ∨  𝑥  ∈  𝐷 ) )  →  ( ( 𝑦  ∈  𝐼  →  ( 𝑥  ≠  𝑦  →  ( 𝑆 ‘ 𝑥 )  ⊆  ( 𝑍 ‘ ( 𝑆 ‘ 𝑦 ) ) ) )  ∧  ( ( 𝑆 ‘ 𝑥 )  ∩  ( ( mrCls ‘ ( SubGrp ‘ 𝐺 ) ) ‘ ∪  ( 𝑆  “  ( 𝐼  ∖  { 𝑥 } ) ) ) )  ⊆  {  0  } ) )  | 
						
						
							| 43 | 
							
								42
							 | 
							simpld | 
							⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐶  ∨  𝑥  ∈  𝐷 ) )  →  ( 𝑦  ∈  𝐼  →  ( 𝑥  ≠  𝑦  →  ( 𝑆 ‘ 𝑥 )  ⊆  ( 𝑍 ‘ ( 𝑆 ‘ 𝑦 ) ) ) ) )  | 
						
						
							| 44 | 
							
								43
							 | 
							ex | 
							⊢ ( 𝜑  →  ( ( 𝑥  ∈  𝐶  ∨  𝑥  ∈  𝐷 )  →  ( 𝑦  ∈  𝐼  →  ( 𝑥  ≠  𝑦  →  ( 𝑆 ‘ 𝑥 )  ⊆  ( 𝑍 ‘ ( 𝑆 ‘ 𝑦 ) ) ) ) ) )  | 
						
						
							| 45 | 
							
								28 44
							 | 
							sylbid | 
							⊢ ( 𝜑  →  ( 𝑥  ∈  𝐼  →  ( 𝑦  ∈  𝐼  →  ( 𝑥  ≠  𝑦  →  ( 𝑆 ‘ 𝑥 )  ⊆  ( 𝑍 ‘ ( 𝑆 ‘ 𝑦 ) ) ) ) ) )  | 
						
						
							| 46 | 
							
								45
							 | 
							3imp2 | 
							⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐼  ∧  𝑦  ∈  𝐼  ∧  𝑥  ≠  𝑦 ) )  →  ( 𝑆 ‘ 𝑥 )  ⊆  ( 𝑍 ‘ ( 𝑆 ‘ 𝑦 ) ) )  | 
						
						
							| 47 | 
							
								28
							 | 
							biimpa | 
							⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐼 )  →  ( 𝑥  ∈  𝐶  ∨  𝑥  ∈  𝐷 ) )  | 
						
						
							| 48 | 
							
								29
							 | 
							simprd | 
							⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐶 )  →  ( ( 𝑆 ‘ 𝑥 )  ∩  ( ( mrCls ‘ ( SubGrp ‘ 𝐺 ) ) ‘ ∪  ( 𝑆  “  ( 𝐼  ∖  { 𝑥 } ) ) ) )  ⊆  {  0  } )  | 
						
						
							| 49 | 
							
								41
							 | 
							simprd | 
							⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐷 )  →  ( ( 𝑆 ‘ 𝑥 )  ∩  ( ( mrCls ‘ ( SubGrp ‘ 𝐺 ) ) ‘ ∪  ( 𝑆  “  ( 𝐼  ∖  { 𝑥 } ) ) ) )  ⊆  {  0  } )  | 
						
						
							| 50 | 
							
								48 49
							 | 
							jaodan | 
							⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐶  ∨  𝑥  ∈  𝐷 ) )  →  ( ( 𝑆 ‘ 𝑥 )  ∩  ( ( mrCls ‘ ( SubGrp ‘ 𝐺 ) ) ‘ ∪  ( 𝑆  “  ( 𝐼  ∖  { 𝑥 } ) ) ) )  ⊆  {  0  } )  | 
						
						
							| 51 | 
							
								47 50
							 | 
							syldan | 
							⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐼 )  →  ( ( 𝑆 ‘ 𝑥 )  ∩  ( ( mrCls ‘ ( SubGrp ‘ 𝐺 ) ) ‘ ∪  ( 𝑆  “  ( 𝐼  ∖  { 𝑥 } ) ) ) )  ⊆  {  0  } )  | 
						
						
							| 52 | 
							
								4 5 10 12 25 1 46 51
							 | 
							dmdprdd | 
							⊢ ( 𝜑  →  𝐺 dom   DProd  𝑆 )  |