  We present a rigorous derivation of dimensionally reduced theories for thin
sheets of nematic elastomers, in the finite bending regime. Focusing on the
case of twist nematic texture, we obtain 2D and 1D models for wide and narrow
ribbons exhibiting spontaneous flexure and torsion. We also discuss some
variants to the case of twist nematic texture, which lead to 2D models with
different target curvature tensors. In particular, we analyse cases where the
nematic texture leads to zero or positive Gaussian target curvature, and the
case of bilayers.
