Finding correspondences between feature points is one
of the most relevant problems in the whole set of visual
tasks. In this paper we address the problem of matching
a feature vector (or a matrix) to a given subspace. Given
any vector base of such a subspace, we observe a linear
combination of its elements with all entries swapped by an
unknown permutation. We prove that such a computationally
hard integer problem is uniquely solved in a convex set
resulting from relaxing the original problem. Also, if noise
is present, based on this result, we provide a robust estimate
recurring to a linear programming-based algorithm. We use
structure-from-motion and object recognition as motivating
examples.