cross-ratio

See also: crossratio

English

Alternative forms

• crossratio

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

a special number associated with an ordered quadruple of collinear points, particularly points on a projective line, and preserved by the fractional linear transformations

• French: birapport m