sentence1: in fda , lian suggested the use of the identity operator , while kadri et al showed that it will be more useful to choose other operators than identity that are able to take into account functional properties of the input and output spaces .
sentence2: lian considered the identity operator , while in kadri et al the authors showed that it will be more useful to choose other operators than identity that are able to take into account functional properties of the input and output spaces .