Abstract :
Let K be a number field, and let W be a subspace of KN, Ngreater-or-equal, slanted1. Let V1,…,VM be subspaces of KN of dimension less than dimension of W. We prove the existence of a point of small height in image, providing an explicit upper bound on the height of such a point in terms of heights of W and V1,…,VM. Our main tool is a counting estimate we prove for the number of points of a subspace of KN inside of an adelic cube. As corollaries to our main result we derive an explicit bound on the height of a nonvanishing point for a decomposable form and an effective subspace extension lemma.
Keywords :
Linear forms , height , Diophantine approximation , Lattices