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| | Xah: Wallpaper: The Discontinuous Groups |
 | | The elements in our group are rotations and translations, written as r[{x,y},α] and t[{x,y}], where the {x,y} is the center of rotation or a vector specifying a translation. |
 | | As a consequence, a lattice {t[A*m+B*n]} and a rotation r[P,α] guarantees a lattice of rotations {r[P+(A*m+B*n),α]}. |
 | | Together with the transitivity of rotations theorem, we have the general result that a lattice {t[P*m+Q*n]} and a 2-fold rotation r[C,2*π/2] guarantees a lattice of 2-fold rotations {r[C+(P*m+Q*n),2*π/2]} and 2-fold rotations on all midpoints of the lattice {r[C+(P*m+Q*n)/2,2*π/2]}. |
| xahlee.org /Wallpaper_dir/c3_Group.html (2091 words) |
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