cross-ratio

See also: crossratio

English

Alternative forms

Etymology

From cross- +‎ ratio.

Noun

cross-ratio (plural cross-ratios)

  1. (geometry) A special number associated with an ordered quadruple of collinear points, particularly points on a projective line, and preserved by the fractional linear transformations.

Synonyms

  • anharmonic ratio
  • double ratio

Translations