| 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 |  | preq2 |  |-  ( ( Y .+ Z ) = .0. -> { X , ( Y .+ Z ) } = { X , .0. } ) | 
						
							| 14 | 13 | fveq2d |  |-  ( ( Y .+ Z ) = .0. -> ( N ` { X , ( Y .+ Z ) } ) = ( N ` { X , .0. } ) ) | 
						
							| 15 |  | lveclmod |  |-  ( W e. LVec -> W e. LMod ) | 
						
							| 16 | 5 15 | syl |  |-  ( ph -> W e. LMod ) | 
						
							| 17 | 6 | eldifad |  |-  ( ph -> X e. V ) | 
						
							| 18 | 1 3 4 16 17 | lsppr0 |  |-  ( ph -> ( N ` { X , .0. } ) = ( N ` { X } ) ) | 
						
							| 19 | 14 18 | sylan9eqr |  |-  ( ( ph /\ ( Y .+ Z ) = .0. ) -> ( N ` { X , ( Y .+ Z ) } ) = ( N ` { X } ) ) | 
						
							| 20 | 7 | eldifad |  |-  ( ph -> Y e. V ) | 
						
							| 21 |  | prssi |  |-  ( ( X e. V /\ Y e. V ) -> { X , Y } C_ V ) | 
						
							| 22 | 17 20 21 | syl2anc |  |-  ( ph -> { X , Y } C_ V ) | 
						
							| 23 |  | snsspr1 |  |-  { X } C_ { X , Y } | 
						
							| 24 | 23 | a1i |  |-  ( ph -> { X } C_ { X , Y } ) | 
						
							| 25 | 1 4 | lspss |  |-  ( ( W e. LMod /\ { X , Y } C_ V /\ { X } C_ { X , Y } ) -> ( N ` { X } ) C_ ( N ` { X , Y } ) ) | 
						
							| 26 | 16 22 24 25 | syl3anc |  |-  ( ph -> ( N ` { X } ) C_ ( N ` { X , Y } ) ) | 
						
							| 27 | 26 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) = .0. ) -> ( N ` { X } ) C_ ( N ` { X , Y } ) ) | 
						
							| 28 | 19 27 | eqsstrd |  |-  ( ( ph /\ ( Y .+ Z ) = .0. ) -> ( N ` { X , ( Y .+ Z ) } ) C_ ( N ` { X , Y } ) ) | 
						
							| 29 | 12 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) = .0. ) -> -. w e. ( N ` { X , Y } ) ) | 
						
							| 30 | 28 29 | ssneldd |  |-  ( ( ph /\ ( Y .+ Z ) = .0. ) -> -. w e. ( N ` { X , ( Y .+ Z ) } ) ) | 
						
							| 31 | 12 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> -. w e. ( N ` { X , Y } ) ) | 
						
							| 32 | 5 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> W e. LVec ) | 
						
							| 33 | 6 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> X e. ( V \ { .0. } ) ) | 
						
							| 34 | 7 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> Y e. ( V \ { .0. } ) ) | 
						
							| 35 | 8 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> Z e. ( V \ { .0. } ) ) | 
						
							| 36 | 9 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> w e. ( V \ { .0. } ) ) | 
						
							| 37 | 10 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> ( N ` { Y } ) = ( N ` { Z } ) ) | 
						
							| 38 | 11 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> ( N ` { X } ) =/= ( N ` { Y } ) ) | 
						
							| 39 |  | simpr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> ( Y .+ Z ) =/= .0. ) | 
						
							| 40 | 1 2 3 4 32 33 34 35 36 37 38 31 39 | mapdindp0 |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> ( N ` { ( Y .+ Z ) } ) = ( N ` { Y } ) ) | 
						
							| 41 | 40 | oveq2d |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> ( ( N ` { X } ) ( LSSum ` W ) ( N ` { ( Y .+ Z ) } ) ) = ( ( N ` { X } ) ( LSSum ` W ) ( N ` { Y } ) ) ) | 
						
							| 42 |  | eqid |  |-  ( LSSum ` W ) = ( LSSum ` W ) | 
						
							| 43 | 8 | eldifad |  |-  ( ph -> Z e. V ) | 
						
							| 44 | 1 2 | lmodvacl |  |-  ( ( W e. LMod /\ Y e. V /\ Z e. V ) -> ( Y .+ Z ) e. V ) | 
						
							| 45 | 16 20 43 44 | syl3anc |  |-  ( ph -> ( Y .+ Z ) e. V ) | 
						
							| 46 | 1 4 42 16 17 45 | lsmpr |  |-  ( ph -> ( N ` { X , ( Y .+ Z ) } ) = ( ( N ` { X } ) ( LSSum ` W ) ( N ` { ( Y .+ Z ) } ) ) ) | 
						
							| 47 | 46 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> ( N ` { X , ( Y .+ Z ) } ) = ( ( N ` { X } ) ( LSSum ` W ) ( N ` { ( Y .+ Z ) } ) ) ) | 
						
							| 48 | 1 4 42 16 17 20 | lsmpr |  |-  ( ph -> ( N ` { X , Y } ) = ( ( N ` { X } ) ( LSSum ` W ) ( N ` { Y } ) ) ) | 
						
							| 49 | 48 | adantr |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> ( N ` { X , Y } ) = ( ( N ` { X } ) ( LSSum ` W ) ( N ` { Y } ) ) ) | 
						
							| 50 | 41 47 49 | 3eqtr4d |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> ( N ` { X , ( Y .+ Z ) } ) = ( N ` { X , Y } ) ) | 
						
							| 51 | 31 50 | neleqtrrd |  |-  ( ( ph /\ ( Y .+ Z ) =/= .0. ) -> -. w e. ( N ` { X , ( Y .+ Z ) } ) ) | 
						
							| 52 | 30 51 | pm2.61dane |  |-  ( ph -> -. w e. ( N ` { X , ( Y .+ Z ) } ) ) |