  We say that a subset of a symplectic manifold is symplectically
(neighbourhood) excisable if its complement is symplectomorphic to the ambient
manifold, (through a symplectomorphism that can be chosen to be the identity
outside an arbitrarily small neighbourhood of the subset). We use
time-independent Hamiltonian flows, and their iterations, to show that certain
properly embedded subsets of noncompact symplectic manifolds are symplectically
neighbourhood excisable: a ray, a "Cantor brush", a "box with a tail", and --
more generally -- epigraphs of lower semi-continuous functions; as well as a
"ray with two horns", and -- more generally -- open-rooted finite trees.
