sentence1: in , the attractor solution was also studied , finding that the results for the spectral index and tensor-to-scalar ratio are basically the same as in the pure higgs or starobinsky case and isocurvature perturbations are small .
sentence2: the attractor solutions were also studied in , finding that the spectral index and tensor-to-scalar ratio are close to the pure higgs or starobinsky case with small isocurvature perturbations .