T-duality constraint on R-R couplings

It has been speculated that the metric, $B$-field and dilaton couplings in the low energy effective action of string theory at any order of $\alpha'$ may be found by imposing the gauge symmetries and the T-duality on the effective action. This proposal can be extended to include the Ramond-Ramond (R-R) couplings as well. In this paper, we first find the dimensional reduction of the R-R fields and then perform explicitly the T-duality constraint on the R-R couplings at the supergravity level. Up to an overall factor, it reproduces the democratic form of the R-R couplings.