Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Using decompositions similar to those of Caponnetto et al., 2007; Sriperumbudur et al., 2017, we apply concentration inequalities on the general Hilbert space H to get a probabilistic bound on the estimation error of order O( 1
λ √ n ).
Category: