| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mapdindp1.v |  |-  V = ( Base ` W ) | 
						
							| 2 |  | mapdindp1.p |  |-  .+ = ( +g ` W ) | 
						
							| 3 |  | mapdindp1.o |  |-  .0. = ( 0g ` W ) | 
						
							| 4 |  | mapdindp1.n |  |-  N = ( LSpan ` W ) | 
						
							| 5 |  | mapdindp1.w |  |-  ( ph -> W e. LVec ) | 
						
							| 6 |  | mapdindp1.x |  |-  ( ph -> X e. ( V \ { .0. } ) ) | 
						
							| 7 |  | mapdindp1.y |  |-  ( ph -> Y e. ( V \ { .0. } ) ) | 
						
							| 8 |  | mapdindp1.z |  |-  ( ph -> Z e. ( V \ { .0. } ) ) | 
						
							| 9 |  | mapdindp1.W |  |-  ( ph -> w e. ( V \ { .0. } ) ) | 
						
							| 10 |  | mapdindp1.e |  |-  ( ph -> ( N ` { Y } ) = ( N ` { Z } ) ) | 
						
							| 11 |  | mapdindp1.ne |  |-  ( ph -> ( N ` { X } ) =/= ( N ` { Y } ) ) | 
						
							| 12 |  | mapdindp1.f |  |-  ( ph -> -. w e. ( N ` { X , Y } ) ) | 
						
							| 13 |  | mapdindp1.yz |  |-  ( ph -> ( Y .+ Z ) =/= .0. ) | 
						
							| 14 |  | eqid |  |-  ( LSubSp ` W ) = ( LSubSp ` W ) | 
						
							| 15 |  | lveclmod |  |-  ( W e. LVec -> W e. LMod ) | 
						
							| 16 | 5 15 | syl |  |-  ( ph -> W e. LMod ) | 
						
							| 17 | 7 | eldifad |  |-  ( ph -> Y e. V ) | 
						
							| 18 | 1 14 4 | lspsncl |  |-  ( ( W e. LMod /\ Y e. V ) -> ( N ` { Y } ) e. ( LSubSp ` W ) ) | 
						
							| 19 | 16 17 18 | syl2anc |  |-  ( ph -> ( N ` { Y } ) e. ( LSubSp ` W ) ) | 
						
							| 20 | 10 19 | eqeltrrd |  |-  ( ph -> ( N ` { Z } ) e. ( LSubSp ` W ) ) | 
						
							| 21 |  | eqid |  |-  ( LSSum ` W ) = ( LSSum ` W ) | 
						
							| 22 | 14 21 | lsmcl |  |-  ( ( W e. LMod /\ ( N ` { Y } ) e. ( LSubSp ` W ) /\ ( N ` { Z } ) e. ( LSubSp ` W ) ) -> ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Z } ) ) e. ( LSubSp ` W ) ) | 
						
							| 23 | 16 19 20 22 | syl3anc |  |-  ( ph -> ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Z } ) ) e. ( LSubSp ` W ) ) | 
						
							| 24 | 14 | lsssssubg |  |-  ( W e. LMod -> ( LSubSp ` W ) C_ ( SubGrp ` W ) ) | 
						
							| 25 | 16 24 | syl |  |-  ( ph -> ( LSubSp ` W ) C_ ( SubGrp ` W ) ) | 
						
							| 26 | 25 19 | sseldd |  |-  ( ph -> ( N ` { Y } ) e. ( SubGrp ` W ) ) | 
						
							| 27 | 10 26 | eqeltrrd |  |-  ( ph -> ( N ` { Z } ) e. ( SubGrp ` W ) ) | 
						
							| 28 | 1 4 | lspsnid |  |-  ( ( W e. LMod /\ Y e. V ) -> Y e. ( N ` { Y } ) ) | 
						
							| 29 | 16 17 28 | syl2anc |  |-  ( ph -> Y e. ( N ` { Y } ) ) | 
						
							| 30 | 8 | eldifad |  |-  ( ph -> Z e. V ) | 
						
							| 31 | 1 4 | lspsnid |  |-  ( ( W e. LMod /\ Z e. V ) -> Z e. ( N ` { Z } ) ) | 
						
							| 32 | 16 30 31 | syl2anc |  |-  ( ph -> Z e. ( N ` { Z } ) ) | 
						
							| 33 | 2 21 | lsmelvali |  |-  ( ( ( ( N ` { Y } ) e. ( SubGrp ` W ) /\ ( N ` { Z } ) e. ( SubGrp ` W ) ) /\ ( Y e. ( N ` { Y } ) /\ Z e. ( N ` { Z } ) ) ) -> ( Y .+ Z ) e. ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Z } ) ) ) | 
						
							| 34 | 26 27 29 32 33 | syl22anc |  |-  ( ph -> ( Y .+ Z ) e. ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Z } ) ) ) | 
						
							| 35 | 14 4 16 23 34 | ellspsn5 |  |-  ( ph -> ( N ` { ( Y .+ Z ) } ) C_ ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Z } ) ) ) | 
						
							| 36 | 10 | oveq2d |  |-  ( ph -> ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Y } ) ) = ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Z } ) ) ) | 
						
							| 37 | 21 | lsmidm |  |-  ( ( N ` { Y } ) e. ( SubGrp ` W ) -> ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Y } ) ) = ( N ` { Y } ) ) | 
						
							| 38 | 26 37 | syl |  |-  ( ph -> ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Y } ) ) = ( N ` { Y } ) ) | 
						
							| 39 | 36 38 | eqtr3d |  |-  ( ph -> ( ( N ` { Y } ) ( LSSum ` W ) ( N ` { Z } ) ) = ( N ` { Y } ) ) | 
						
							| 40 | 35 39 | sseqtrd |  |-  ( ph -> ( N ` { ( Y .+ Z ) } ) C_ ( N ` { Y } ) ) | 
						
							| 41 | 1 2 | lmodvacl |  |-  ( ( W e. LMod /\ Y e. V /\ Z e. V ) -> ( Y .+ Z ) e. V ) | 
						
							| 42 | 16 17 30 41 | syl3anc |  |-  ( ph -> ( Y .+ Z ) e. V ) | 
						
							| 43 |  | eldifsn |  |-  ( ( Y .+ Z ) e. ( V \ { .0. } ) <-> ( ( Y .+ Z ) e. V /\ ( Y .+ Z ) =/= .0. ) ) | 
						
							| 44 | 42 13 43 | sylanbrc |  |-  ( ph -> ( Y .+ Z ) e. ( V \ { .0. } ) ) | 
						
							| 45 | 1 3 4 5 44 17 | lspsncmp |  |-  ( ph -> ( ( N ` { ( Y .+ Z ) } ) C_ ( N ` { Y } ) <-> ( N ` { ( Y .+ Z ) } ) = ( N ` { Y } ) ) ) | 
						
							| 46 | 40 45 | mpbid |  |-  ( ph -> ( N ` { ( Y .+ Z ) } ) = ( N ` { Y } ) ) |