Manifold with an orientation-reversing self-homeomorphism

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Definition

A connected orientable manifold is termed a manifold with an orientation-reversing self-homeomorphism if there is a homeomorphism from the manifold to itself that, if applied to any orientation of the manifold, produces the opposite orientation.

For a compact connected orientable manifold

For a compact connected orientable manifold, a self-homeomorphism is orientation-reversing if it induces the multiplication by 1 map on the top homology, or equivalently, sends a fundamental class to its negative. A manifold with an orientation-reversing self-homeomorphism is thus a manifold for which there exists a self-homeomorphism with such an effect.

Examples

Below are some examples of compact connected orientable manifolds and whether or not they have orientation-reversing self-homeomorphisms:

Manifold or family of manifolds Dimension in terms of parameter For what values of the parameter does it have an orientation-reversing self-homeomorphism? Proof/explanation
sphere Sn, n1 n all reflection in any one coordinate, keeping the other coordinates fixed.
real projective space Pn(R), n odd n all odd n (note: for n even, the manifold isn't orientable to begin with, so the question doesn't make sense) use the reflection in any one coordinate orientation-reversing self-homeomorphism of the sphere, descend it to real projective space (this is possible because the operation commutes with the antipodal map).
complex projective space Pn(C) 2n all odd n complex projective space has orientation-reversing self-homeomorphism iff it has odd complex dimension
compact orientable surface, genus g0 2 all g compact orientable surface possesses orientation-reversing self-homeomorphism

Facts

  • Given two connected orientable manifolds M1 and M2, if either of them possesses an orientation-reversing self-homeomorphism, so does the product M1×M2. The trick is to take the Cartesian product of the orientation-reversing self-homeomorphism on one manifold and the identity map on the other.