| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							dmdprdpr.z | 
							 |-  Z = ( Cntz ` G )  | 
						
						
							| 2 | 
							
								
							 | 
							dmdprdpr.0 | 
							 |-  .0. = ( 0g ` G )  | 
						
						
							| 3 | 
							
								
							 | 
							dmdprdpr.s | 
							 |-  ( ph -> S e. ( SubGrp ` G ) )  | 
						
						
							| 4 | 
							
								
							 | 
							dmdprdpr.t | 
							 |-  ( ph -> T e. ( SubGrp ` G ) )  | 
						
						
							| 5 | 
							
								
							 | 
							0ex | 
							 |-  (/) e. _V  | 
						
						
							| 6 | 
							
								
							 | 
							dprdsn | 
							 |-  ( ( (/) e. _V /\ S e. ( SubGrp ` G ) ) -> ( G dom DProd { <. (/) , S >. } /\ ( G DProd { <. (/) , S >. } ) = S ) ) | 
						
						
							| 7 | 
							
								5 3 6
							 | 
							sylancr | 
							 |-  ( ph -> ( G dom DProd { <. (/) , S >. } /\ ( G DProd { <. (/) , S >. } ) = S ) ) | 
						
						
							| 8 | 
							
								7
							 | 
							simpld | 
							 |-  ( ph -> G dom DProd { <. (/) , S >. } ) | 
						
						
							| 9 | 
							
								
							 | 
							xpscf | 
							 |-  ( { <. (/) , S >. , <. 1o , T >. } : 2o --> ( SubGrp ` G ) <-> ( S e. ( SubGrp ` G ) /\ T e. ( SubGrp ` G ) ) ) | 
						
						
							| 10 | 
							
								3 4 9
							 | 
							sylanbrc | 
							 |-  ( ph -> { <. (/) , S >. , <. 1o , T >. } : 2o --> ( SubGrp ` G ) ) | 
						
						
							| 11 | 
							
								10
							 | 
							ffnd | 
							 |-  ( ph -> { <. (/) , S >. , <. 1o , T >. } Fn 2o ) | 
						
						
							| 12 | 
							
								5
							 | 
							prid1 | 
							 |-  (/) e. { (/) , 1o } | 
						
						
							| 13 | 
							
								
							 | 
							df2o3 | 
							 |-  2o = { (/) , 1o } | 
						
						
							| 14 | 
							
								12 13
							 | 
							eleqtrri | 
							 |-  (/) e. 2o  | 
						
						
							| 15 | 
							
								
							 | 
							fnressn | 
							 |-  ( ( { <. (/) , S >. , <. 1o , T >. } Fn 2o /\ (/) e. 2o ) -> ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) = { <. (/) , ( { <. (/) , S >. , <. 1o , T >. } ` (/) ) >. } ) | 
						
						
							| 16 | 
							
								11 14 15
							 | 
							sylancl | 
							 |-  ( ph -> ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) = { <. (/) , ( { <. (/) , S >. , <. 1o , T >. } ` (/) ) >. } ) | 
						
						
							| 17 | 
							
								
							 | 
							fvpr0o | 
							 |-  ( S e. ( SubGrp ` G ) -> ( { <. (/) , S >. , <. 1o , T >. } ` (/) ) = S ) | 
						
						
							| 18 | 
							
								3 17
							 | 
							syl | 
							 |-  ( ph -> ( { <. (/) , S >. , <. 1o , T >. } ` (/) ) = S ) | 
						
						
							| 19 | 
							
								18
							 | 
							opeq2d | 
							 |-  ( ph -> <. (/) , ( { <. (/) , S >. , <. 1o , T >. } ` (/) ) >. = <. (/) , S >. ) | 
						
						
							| 20 | 
							
								19
							 | 
							sneqd | 
							 |-  ( ph -> { <. (/) , ( { <. (/) , S >. , <. 1o , T >. } ` (/) ) >. } = { <. (/) , S >. } ) | 
						
						
							| 21 | 
							
								16 20
							 | 
							eqtrd | 
							 |-  ( ph -> ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) = { <. (/) , S >. } ) | 
						
						
							| 22 | 
							
								8 21
							 | 
							breqtrrd | 
							 |-  ( ph -> G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) | 
						
						
							| 23 | 
							
								
							 | 
							1on | 
							 |-  1o e. On  | 
						
						
							| 24 | 
							
								
							 | 
							dprdsn | 
							 |-  ( ( 1o e. On /\ T e. ( SubGrp ` G ) ) -> ( G dom DProd { <. 1o , T >. } /\ ( G DProd { <. 1o , T >. } ) = T ) ) | 
						
						
							| 25 | 
							
								23 4 24
							 | 
							sylancr | 
							 |-  ( ph -> ( G dom DProd { <. 1o , T >. } /\ ( G DProd { <. 1o , T >. } ) = T ) ) | 
						
						
							| 26 | 
							
								25
							 | 
							simpld | 
							 |-  ( ph -> G dom DProd { <. 1o , T >. } ) | 
						
						
							| 27 | 
							
								
							 | 
							1oex | 
							 |-  1o e. _V  | 
						
						
							| 28 | 
							
								27
							 | 
							prid2 | 
							 |-  1o e. { (/) , 1o } | 
						
						
							| 29 | 
							
								28 13
							 | 
							eleqtrri | 
							 |-  1o e. 2o  | 
						
						
							| 30 | 
							
								
							 | 
							fnressn | 
							 |-  ( ( { <. (/) , S >. , <. 1o , T >. } Fn 2o /\ 1o e. 2o ) -> ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) = { <. 1o , ( { <. (/) , S >. , <. 1o , T >. } ` 1o ) >. } ) | 
						
						
							| 31 | 
							
								11 29 30
							 | 
							sylancl | 
							 |-  ( ph -> ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) = { <. 1o , ( { <. (/) , S >. , <. 1o , T >. } ` 1o ) >. } ) | 
						
						
							| 32 | 
							
								
							 | 
							fvpr1o | 
							 |-  ( T e. ( SubGrp ` G ) -> ( { <. (/) , S >. , <. 1o , T >. } ` 1o ) = T ) | 
						
						
							| 33 | 
							
								4 32
							 | 
							syl | 
							 |-  ( ph -> ( { <. (/) , S >. , <. 1o , T >. } ` 1o ) = T ) | 
						
						
							| 34 | 
							
								33
							 | 
							opeq2d | 
							 |-  ( ph -> <. 1o , ( { <. (/) , S >. , <. 1o , T >. } ` 1o ) >. = <. 1o , T >. ) | 
						
						
							| 35 | 
							
								34
							 | 
							sneqd | 
							 |-  ( ph -> { <. 1o , ( { <. (/) , S >. , <. 1o , T >. } ` 1o ) >. } = { <. 1o , T >. } ) | 
						
						
							| 36 | 
							
								31 35
							 | 
							eqtrd | 
							 |-  ( ph -> ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) = { <. 1o , T >. } ) | 
						
						
							| 37 | 
							
								26 36
							 | 
							breqtrrd | 
							 |-  ( ph -> G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) | 
						
						
							| 38 | 
							
								
							 | 
							1n0 | 
							 |-  1o =/= (/)  | 
						
						
							| 39 | 
							
								38
							 | 
							necomi | 
							 |-  (/) =/= 1o  | 
						
						
							| 40 | 
							
								
							 | 
							disjsn2 | 
							 |-  ( (/) =/= 1o -> ( { (/) } i^i { 1o } ) = (/) ) | 
						
						
							| 41 | 
							
								39 40
							 | 
							mp1i | 
							 |-  ( ph -> ( { (/) } i^i { 1o } ) = (/) ) | 
						
						
							| 42 | 
							
								
							 | 
							df-pr | 
							 |-  { (/) , 1o } = ( { (/) } u. { 1o } ) | 
						
						
							| 43 | 
							
								13 42
							 | 
							eqtri | 
							 |-  2o = ( { (/) } u. { 1o } ) | 
						
						
							| 44 | 
							
								43
							 | 
							a1i | 
							 |-  ( ph -> 2o = ( { (/) } u. { 1o } ) ) | 
						
						
							| 45 | 
							
								10 41 44 1 2
							 | 
							dmdprdsplit | 
							 |-  ( ph -> ( G dom DProd { <. (/) , S >. , <. 1o , T >. } <-> ( ( G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) /\ G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) /\ ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) C_ ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = { .0. } ) ) ) | 
						
						
							| 46 | 
							
								
							 | 
							3anass | 
							 |-  ( ( ( G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) /\ G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) /\ ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) C_ ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = { .0. } ) <-> ( ( G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) /\ G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) C_ ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = { .0. } ) ) ) | 
						
						
							| 47 | 
							
								45 46
							 | 
							bitrdi | 
							 |-  ( ph -> ( G dom DProd { <. (/) , S >. , <. 1o , T >. } <-> ( ( G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) /\ G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) C_ ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = { .0. } ) ) ) ) | 
						
						
							| 48 | 
							
								47
							 | 
							baibd | 
							 |-  ( ( ph /\ ( G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) /\ G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) -> ( G dom DProd { <. (/) , S >. , <. 1o , T >. } <-> ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) C_ ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = { .0. } ) ) ) | 
						
						
							| 49 | 
							
								48
							 | 
							ex | 
							 |-  ( ph -> ( ( G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) /\ G dom DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) -> ( G dom DProd { <. (/) , S >. , <. 1o , T >. } <-> ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) C_ ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = { .0. } ) ) ) ) | 
						
						
							| 50 | 
							
								22 37 49
							 | 
							mp2and | 
							 |-  ( ph -> ( G dom DProd { <. (/) , S >. , <. 1o , T >. } <-> ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) C_ ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = { .0. } ) ) ) | 
						
						
							| 51 | 
							
								21
							 | 
							oveq2d | 
							 |-  ( ph -> ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) = ( G DProd { <. (/) , S >. } ) ) | 
						
						
							| 52 | 
							
								7
							 | 
							simprd | 
							 |-  ( ph -> ( G DProd { <. (/) , S >. } ) = S ) | 
						
						
							| 53 | 
							
								51 52
							 | 
							eqtrd | 
							 |-  ( ph -> ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) = S ) | 
						
						
							| 54 | 
							
								36
							 | 
							oveq2d | 
							 |-  ( ph -> ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) = ( G DProd { <. 1o , T >. } ) ) | 
						
						
							| 55 | 
							
								25
							 | 
							simprd | 
							 |-  ( ph -> ( G DProd { <. 1o , T >. } ) = T ) | 
						
						
							| 56 | 
							
								54 55
							 | 
							eqtrd | 
							 |-  ( ph -> ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) = T ) | 
						
						
							| 57 | 
							
								56
							 | 
							fveq2d | 
							 |-  ( ph -> ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = ( Z ` T ) ) | 
						
						
							| 58 | 
							
								53 57
							 | 
							sseq12d | 
							 |-  ( ph -> ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) C_ ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) <-> S C_ ( Z ` T ) ) ) | 
						
						
							| 59 | 
							
								53 56
							 | 
							ineq12d | 
							 |-  ( ph -> ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = ( S i^i T ) ) | 
						
						
							| 60 | 
							
								59
							 | 
							eqeq1d | 
							 |-  ( ph -> ( ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = { .0. } <-> ( S i^i T ) = { .0. } ) ) | 
						
						
							| 61 | 
							
								58 60
							 | 
							anbi12d | 
							 |-  ( ph -> ( ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) C_ ( Z ` ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) /\ ( ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { (/) } ) ) i^i ( G DProd ( { <. (/) , S >. , <. 1o , T >. } |` { 1o } ) ) ) = { .0. } ) <-> ( S C_ ( Z ` T ) /\ ( S i^i T ) = { .0. } ) ) ) | 
						
						
							| 62 | 
							
								50 61
							 | 
							bitrd | 
							 |-  ( ph -> ( G dom DProd { <. (/) , S >. , <. 1o , T >. } <-> ( S C_ ( Z ` T ) /\ ( S i^i T ) = { .0. } ) ) ) |