Simple Spherical Venn diagrams with Isometry Groups of Order Eight
نویسندگان
چکیده
For each n ≥ 4 we show how to construct simple Venn diagrams of n curves embedded on the sphere with the following sets of isometries: (a) a 4-fold rotational symmetry about the polar axis, together with an additional involutional symmetry about an axis through the equator, and (b) an involutional symmetry about the polar axis together with two reflectional symmetries about orthogonal planes that intersect at the polar axis. In both cases (a) and (b) the order of the group of isometries is 8.
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