Abstract: | Differential geometry has discovered many objects which determine Lie algebroids playing a role analogous to that of Lie algebras for Lie groups. For example: --- differential groupoids, --- principal bundles, --- vector bundles, --- actions of Lie groups on manifolds, --- transversally complete foliations, --- nonclosed Lie subgroups, --- Poisson manifolds, --- some complete closed pseudogroups. We carry over the idea of Bott's Vanishing Theorem to regular Lie algebroids (using the Chern-Weil homomorphism of transitive Lie algebroids investigated by the author) and, next, apply it to new situations which are not described by the classical version, for example, to the theory of transversally complete foliations and nonclosed Lie subgroups in order to obtain some topological obstructions for the existence of involutive distributions and Lie subalgebras of some types (respectively). |