Abstract. We introduce a class of special geometries associated to the choice of a differential graded algebra contained in Λ * R n . We generalize some known embedding results, that effectively characterize the real analytic Riemannian manifolds that can be realized as submanifolds of a Riemannian manifold with special holonomy, to this more general context. In particular, we consider the case of hypersurfaces inside nearly-Kähler and α-Einstein-Sasaki manifolds, proving that the corresponding evolution equations always admit a solution in the real analytic case.There are a number of known results concerning the problem of embedding a generic Riemannian manifold into a manifold with special holonomy. At the very least for this problem to make sense the embedding should be isometric, but often extra conditions are required. A classical example is that of special Lagrangian submanifolds of Calabi-Yau manifolds, introduced in [15] in the context of minimal submanifolds; it is a result of [8] that every compact, oriented real analytic Riemannian 3-manifold can be embedded isometrically as a special Lagrangian submanifold in a 6-manifold with holonomy contained in SU(3) (see also [18] for a generalization). A similar result holds for coassociative submanifolds in 7-manifolds with holonomy contained in G 2 (see [8]); the case of codimension one embeddings in manifolds with special holonomy was considered in [16,13].Whilst the above results have been obtained using characterizations in terms of differential forms, the codimension one embedding problem can be uniformly rephrased using the language of spinors. Indeed, if M is a Riemannian spin manifold with a parallel spinor, then a hypersurface inherits a generalized Killing spinor ψ, namely satisfyingwhere A is a section of the bundle of symmetric endomorphism of T M , corresponding to the Weingarten tensor, and the dot represents Clifford multiplication. One can ask if, given a Riemannian spin manifold (N, g) with a generalized Killing spinor ψ, the spinor can be extended to a parallel spinor on a Riemannian manifold M ⊃ N containing N as a hypersurface; if so, M is Ricci flat and the second fundamental form is determined by the tensor A, which is an intrinsic property of (N, g, ψ). Counterexamples exist in the smooth category [6]; in the real analytic category, the general existence of such an embedding has been established in [3] under the assumption that the tensor A is Codazzi, and in [13] for six-dimensional N .