Wemma an linearen Unterraum U = span B ′ {\displaystyle U=\operatorname {span} \;{\mathcal {B}}'} hod, nachernd gitz a Basis B {\displaystyle {\mathcal {B}}} von U {\displaystyle U} , de wej Teilmenge vo B ′ {\displaystyle {\mathcal {B}}'} is.