Let be a torus, and let be the complement of a point in . Find a subset of which is homeomorphic to a figure "8" curve (i.e. the union of two circles with a single point in common) and which is a deformation retract of .
solved it
Let be a torus, and let be the complement of a point in . Find a subset of which is homeomorphic to a figure "8" curve (i.e. the union of two circles with a single point in common) and which is a deformation retract of .
solved it