Consider a generic
n-dimensional subbundle 𝒱 of the tangent bundle TM on some manifold M. Given 𝒱,
one can define different degeneracy loci Σr(𝒱), r = (r1≤ r2≤ r3≤⋯≤ rk), on M
consisting of all points x ∈ M for which the subspaces 𝒱j(x) ⊂ TM(x) spanned by all
length ≤ j commutators of vector fields tangent to 𝒱 at x has dimension less
than or equal to rj. Under a certain transversality assumption, we explicitly
calculate the ℤ2-cohomology classes of M dual to Σr(𝒱), using determinantal
formulas due to W. Fulton and the expression of the Chern classes of the
associated bundle of the free Lie algebras in terms of the Chern classes of
𝒱.