Cosmological evolution in f(T, B) gravity

For the fourth-order teleparallel $$f\left( T,B\right) $$ theory of gravity, we investigate cosmological evolution for universe in case a spatially flat Friedmann–Lemaître–Robertson–Walker background space. We focus on which is separable, that is, _{,TB}=0$$ and nonlinear function scalars T B. this theory, use Lagrange multiplier to introduce scalar field attributes higher-order derivatives. In order perform analysis dynamics, dimensionless variables allow Hubble change sign. The stationary points dynamical system are investigated both finite infinite regimes. physical properties asymptotic solutions their stability characteristics discussed.