| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lspsncmp.v |  |-  V = ( Base ` W ) | 
						
							| 2 |  | lspsncmp.o |  |-  .0. = ( 0g ` W ) | 
						
							| 3 |  | lspsncmp.n |  |-  N = ( LSpan ` W ) | 
						
							| 4 |  | lspsncmp.w |  |-  ( ph -> W e. LVec ) | 
						
							| 5 |  | lspsncmp.x |  |-  ( ph -> X e. ( V \ { .0. } ) ) | 
						
							| 6 |  | lspsncmp.y |  |-  ( ph -> Y e. V ) | 
						
							| 7 | 4 | adantr |  |-  ( ( ph /\ ( N ` { X } ) C_ ( N ` { Y } ) ) -> W e. LVec ) | 
						
							| 8 | 6 | adantr |  |-  ( ( ph /\ ( N ` { X } ) C_ ( N ` { Y } ) ) -> Y e. V ) | 
						
							| 9 |  | eqid |  |-  ( LSubSp ` W ) = ( LSubSp ` W ) | 
						
							| 10 |  | lveclmod |  |-  ( W e. LVec -> W e. LMod ) | 
						
							| 11 | 4 10 | syl |  |-  ( ph -> W e. LMod ) | 
						
							| 12 | 1 9 3 | lspsncl |  |-  ( ( W e. LMod /\ Y e. V ) -> ( N ` { Y } ) e. ( LSubSp ` W ) ) | 
						
							| 13 | 11 6 12 | syl2anc |  |-  ( ph -> ( N ` { Y } ) e. ( LSubSp ` W ) ) | 
						
							| 14 | 5 | eldifad |  |-  ( ph -> X e. V ) | 
						
							| 15 | 1 9 3 11 13 14 | ellspsn5b |  |-  ( ph -> ( X e. ( N ` { Y } ) <-> ( N ` { X } ) C_ ( N ` { Y } ) ) ) | 
						
							| 16 | 15 | biimpar |  |-  ( ( ph /\ ( N ` { X } ) C_ ( N ` { Y } ) ) -> X e. ( N ` { Y } ) ) | 
						
							| 17 |  | eldifsni |  |-  ( X e. ( V \ { .0. } ) -> X =/= .0. ) | 
						
							| 18 | 5 17 | syl |  |-  ( ph -> X =/= .0. ) | 
						
							| 19 | 18 | adantr |  |-  ( ( ph /\ ( N ` { X } ) C_ ( N ` { Y } ) ) -> X =/= .0. ) | 
						
							| 20 | 1 2 3 7 8 16 19 | lspsneleq |  |-  ( ( ph /\ ( N ` { X } ) C_ ( N ` { Y } ) ) -> ( N ` { X } ) = ( N ` { Y } ) ) | 
						
							| 21 | 20 | ex |  |-  ( ph -> ( ( N ` { X } ) C_ ( N ` { Y } ) -> ( N ` { X } ) = ( N ` { Y } ) ) ) | 
						
							| 22 |  | eqimss |  |-  ( ( N ` { X } ) = ( N ` { Y } ) -> ( N ` { X } ) C_ ( N ` { Y } ) ) | 
						
							| 23 | 21 22 | impbid1 |  |-  ( ph -> ( ( N ` { X } ) C_ ( N ` { Y } ) <-> ( N ` { X } ) = ( N ` { Y } ) ) ) |