String theories inspire a new formalism for their low-energy limits. In this approach to these eld theories, spacetime duality and stringy left/right handedness are manifest. Enlarged tangent-space symmetries allow the di erent elds (graviton, axion, Yang-Mills) to be treated as a single multiplet, even in the bosonic case, except for the dilaton (multiplet), which appears as the measure.

We consider the effects on cosmology of higher-derivative modifications of (effective) gravity that make it asymptotically free without introducing ghosts. The weakening of gravity at short distances allows pressure to prevent the singularity, producing a solution with contraction preceding expansion.

Using independent left and right vierbeins to describe graviton plus axion as suggested by string mechanics, O(d,d) duality can be realized linearly.