So I'm studying projective geometry and I'm confused about duality. In particular, I'm confused about drawing dual pictures.(adsbygoogle = window.adsbygoogle || []).push({});

If you look at Menelaus's Theorem and Ceva's Theorem, they are supposedly dual diagrams.

http://en.wikipedia.org/wiki/Menelaus'_theorem

http://en.wikipedia.org/wiki/Ceva's_theorem

In the diagram for Menelaus's theorem, there are 6 points and four lines, so that means that there are 6 lines and four points in Ceva's theorem. However, looking at Ceva's theorem, there are indeed 6 lines but there are more than 4 points, there are 7. So how can they be dual diagrams?

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# Confused about Duality in Projective Geometry

Can you offer guidance or do you also need help?

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