2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/211062If inflation is to be considered in an unbiased way, as possibly originating from one of a wide range of underlying theories, then observations need not be simply applied to reconstructing the inflaton potential, V(ϕ), or a specific kinetic term, as in DBI inflation, but rather to reconstruct the inflationary action in its entirety. We discuss the constraints that can be placed on a general single field action from measurements of the primordial scalar and tensor fluctuation power spectra and non-Gaussianities. We also present the flow equation formalism for reconstructing a general inflationary Lagrangian, L(X,ϕ), with X={1/2}\partial_μϕ\partial^μϕ, in a general gauge, that reduces to canonical and DBI inflation in the specific gauge \partial L/\partial X = c_s^{-1}.16 pages, 1 figure, References added, typos correctedAstrophysicsHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext