Fixed-point-free perturbation of a doubled-surface reflection

ID: fixed-point-free-perturbation-of-a-doubled-surface-reflection

Double a compact orientable genus-zero topological surface with boundary circles. The resulting closed surface has genus . The involution exchanging the halves fixes the seam circles and has local collar form . Compose it with a flow rotating each seam coordinate by a small nonzero amount, with speed supported in its collar. Equality with the initial point would force , where the rotation is nonzero; off the collars the original reflection already has no fixed points. The new map is fixed-point-free and homotopic to the reflection through the flow. This gives a surface example in every genus where having fixed points is not a homotopy invariant.

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