Point-pair separation
id:
point-pair-separation-290-15415217
title:
Point-pair separation
text:
In a cyclic order, such as the real projective line, two pairs of points separate each other when they occur alternately in the order. Thus the ordering a b c d of four points has (a,c) and (b,d) as separating pairs. This point-pair separation is an invariant of projectivities of the line. The concept was described by G. B. Halsted at the outset of his Synthetic Projective Geometry: Given any pair of points on a projective line, they separate a third point from its harmonic conjugate. A pair of
brand slug:
wiki
category slug:
encyclopedia
description:
Property of pairs of points in a cyclic order
original url:
https://en.wikipedia.org/wiki/Point-pair_separation
date created:
date modified:
2022-10-05T03:15:39Z
main entity:
{"identifier":"Q108485537","url":"https://www.wikidata.org/entity/Q108485537"}
image:
fields total:
13
integrity:
14