A fixed point theorem for smooth extension maps

Let X be a compact smooth n-manifold, with or without boundary, and let A be an -dimensional smooth submanifold of the interior of X. Let be a smooth map and be a smooth map whose restriction to A is ϕ. If is an isolated fixed point of f that is a transversal fixed point of ϕ, that is, the linear transformation is nonsingular, then the fixed point index of f at p satisfies the inequality . It follows that if ϕ has k fixed points, all transverse, and the Lefschetz number , then there is at least one fixed point of f in . Examples demonstrate that these results do not hold if the maps are not smooth. MSC:55M20, 54C20.