Anisotropic homogeneous string cosmology with two-loop corrections

The two-loop (order α′) β-function equations, which are equivalent to the equations of motion of α′-corrected string effective action, are considered for anisotropic homogeneous space-times. These equations are solved for all Bianchi-type models in two schemes of effective action, namely R2 and Gauss-Bonnet schemes with zero cosmological constant and then the metric, dilaton and B-field are found at α′ perturbative corrections.