| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lspsnss2.v |  |-  V = ( Base ` W ) | 
						
							| 2 |  | lspsnss2.s |  |-  S = ( Scalar ` W ) | 
						
							| 3 |  | lspsnss2.k |  |-  K = ( Base ` S ) | 
						
							| 4 |  | lspsnss2.t |  |-  .x. = ( .s ` W ) | 
						
							| 5 |  | lspsnss2.n |  |-  N = ( LSpan ` W ) | 
						
							| 6 |  | lspsnss2.w |  |-  ( ph -> W e. LMod ) | 
						
							| 7 |  | lspsnss2.x |  |-  ( ph -> X e. V ) | 
						
							| 8 |  | lspsnss2.y |  |-  ( ph -> Y e. V ) | 
						
							| 9 |  | eqid |  |-  ( LSubSp ` W ) = ( LSubSp ` W ) | 
						
							| 10 | 1 9 5 | lspsncl |  |-  ( ( W e. LMod /\ Y e. V ) -> ( N ` { Y } ) e. ( LSubSp ` W ) ) | 
						
							| 11 | 6 8 10 | syl2anc |  |-  ( ph -> ( N ` { Y } ) e. ( LSubSp ` W ) ) | 
						
							| 12 | 1 9 5 6 11 7 | ellspsn5b |  |-  ( ph -> ( X e. ( N ` { Y } ) <-> ( N ` { X } ) C_ ( N ` { Y } ) ) ) | 
						
							| 13 | 2 3 1 4 5 | ellspsn |  |-  ( ( W e. LMod /\ Y e. V ) -> ( X e. ( N ` { Y } ) <-> E. k e. K X = ( k .x. Y ) ) ) | 
						
							| 14 | 6 8 13 | syl2anc |  |-  ( ph -> ( X e. ( N ` { Y } ) <-> E. k e. K X = ( k .x. Y ) ) ) | 
						
							| 15 | 12 14 | bitr3d |  |-  ( ph -> ( ( N ` { X } ) C_ ( N ` { Y } ) <-> E. k e. K X = ( k .x. Y ) ) ) |