{
  "aliases": [
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    "anharmonic-ratio"
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  "body": "\n## Summary\n\nThe cross-ratio is a number made from four points of a line, or of the Riemann sphere, see the [[definition|05MW7MPRBS]].\nIt does not change under [[Möbius transformations|0SG74WBFA2]] and, more generally, under projective transformations.\n",
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