| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lspss.v |  |-  V = ( Base ` W ) | 
						
							| 2 |  | lspss.n |  |-  N = ( LSpan ` W ) | 
						
							| 3 |  | simpl3 |  |-  ( ( ( W e. LMod /\ U C_ V /\ T C_ U ) /\ t e. ( LSubSp ` W ) ) -> T C_ U ) | 
						
							| 4 |  | sstr2 |  |-  ( T C_ U -> ( U C_ t -> T C_ t ) ) | 
						
							| 5 | 3 4 | syl |  |-  ( ( ( W e. LMod /\ U C_ V /\ T C_ U ) /\ t e. ( LSubSp ` W ) ) -> ( U C_ t -> T C_ t ) ) | 
						
							| 6 | 5 | ss2rabdv |  |-  ( ( W e. LMod /\ U C_ V /\ T C_ U ) -> { t e. ( LSubSp ` W ) | U C_ t } C_ { t e. ( LSubSp ` W ) | T C_ t } ) | 
						
							| 7 |  | intss |  |-  ( { t e. ( LSubSp ` W ) | U C_ t } C_ { t e. ( LSubSp ` W ) | T C_ t } -> |^| { t e. ( LSubSp ` W ) | T C_ t } C_ |^| { t e. ( LSubSp ` W ) | U C_ t } ) | 
						
							| 8 | 6 7 | syl |  |-  ( ( W e. LMod /\ U C_ V /\ T C_ U ) -> |^| { t e. ( LSubSp ` W ) | T C_ t } C_ |^| { t e. ( LSubSp ` W ) | U C_ t } ) | 
						
							| 9 |  | simp1 |  |-  ( ( W e. LMod /\ U C_ V /\ T C_ U ) -> W e. LMod ) | 
						
							| 10 |  | simp3 |  |-  ( ( W e. LMod /\ U C_ V /\ T C_ U ) -> T C_ U ) | 
						
							| 11 |  | simp2 |  |-  ( ( W e. LMod /\ U C_ V /\ T C_ U ) -> U C_ V ) | 
						
							| 12 | 10 11 | sstrd |  |-  ( ( W e. LMod /\ U C_ V /\ T C_ U ) -> T C_ V ) | 
						
							| 13 |  | eqid |  |-  ( LSubSp ` W ) = ( LSubSp ` W ) | 
						
							| 14 | 1 13 2 | lspval |  |-  ( ( W e. LMod /\ T C_ V ) -> ( N ` T ) = |^| { t e. ( LSubSp ` W ) | T C_ t } ) | 
						
							| 15 | 9 12 14 | syl2anc |  |-  ( ( W e. LMod /\ U C_ V /\ T C_ U ) -> ( N ` T ) = |^| { t e. ( LSubSp ` W ) | T C_ t } ) | 
						
							| 16 | 1 13 2 | lspval |  |-  ( ( W e. LMod /\ U C_ V ) -> ( N ` U ) = |^| { t e. ( LSubSp ` W ) | U C_ t } ) | 
						
							| 17 | 16 | 3adant3 |  |-  ( ( W e. LMod /\ U C_ V /\ T C_ U ) -> ( N ` U ) = |^| { t e. ( LSubSp ` W ) | U C_ t } ) | 
						
							| 18 | 8 15 17 | 3sstr4d |  |-  ( ( W e. LMod /\ U C_ V /\ T C_ U ) -> ( N ` T ) C_ ( N ` U ) ) |