Sentence:  On the other hand , the null space of * * f and the null space of * * f together span V , the <WSD>former</WSD> being the subspace spanned by * * f and the latter the subspace spanned by * * f and * * f . 
Meaning of the word marked with <WSD> tags:  referring to the first of two things or persons mentioned (or the earlier one or ones of several); I prefer the former version to the latter one"