Let ℋ(En) denote the group
of homeomorphisms of euclidean n-space, and G a subgroup isomorphic to Z ⊕Z.G is
said to be a Z2-action on En and two such actions ale said to be equivalent
if they are conjugate in ℋ(En). In §2, the notion of a tame Z2-action is
introduced and for n ≧ 5 tame Z2-actions are shown to be classified by
π1(SOn−2)≅Z2. In §3, tameness is shown to be inherited by a subaction of a tame
Z2-action and an example of a nontame Z2-action with tame subactions is
given.