perplexus.info :: Shapes : 8 points no convex pentagon

8 points no convex pentagon (Posted on 2009-10-09)

Find a set of 8 points with no three collinear such that no subset of 5 forms a convex pentagon.

Submitted by Jer

No Rating

Solution: (Hide)

* * * * * * * *
Any sub set of 5 is either 4 points from one side and 1 from the other or 3 from one side and 2 from the other. Clearly in both cases you will get a concavity.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
solution	Charlie	2009-10-09 17:36:41
re: possible real solution (not proven yet) -counterexample	Jer	2009-10-09 15:32:22
possible real solution (not proven yet)	Daniel	2009-10-09 13:37:53
possible cheat	Daniel	2009-10-09 13:21:31

Please log in:

Login:
Password:
Remember me:

Sign up! \| Forgot password

Search:

Search body:

Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (3)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info