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Topic: Collinear
Replies: 9   Last Post: May 8, 2013 1:12 PM

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 Barry Schwarz Posts: 177 Registered: 3/13/08
Re: Collinear
Posted: May 7, 2013 12:05 PM

On 07/05/2013 08:48, William Elliot wrote:
> Let C be a collection of n points with the property that
> any line L with two points of C on it, has a third point
> of C on it.
>
> How is it that C is collinear, ie all points of C are
> on a single line?

The assertion is not true if points are allowed to be coincident. For
example
P1 = (0,0)
P2 = (1,0)
P3 = (2,0)
P4 = P5 = P6 =(1,1)

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Date Subject Author
5/7/13 William Elliot
5/7/13 David Bernier
5/7/13 William Elliot
5/7/13 David Bernier
5/7/13 LudovicoVan
5/7/13 Robin Chapman
5/7/13 Barry Schwarz
5/8/13 David C. Ullrich
5/7/13 fom
5/7/13 fom