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Dec 12, 2022 at 16:48 comment added Chris Leary @Gerry Myerson - It pays to read questions carefully. Upon rereading, I missed that $f$ was generally to be nonnegative.
Dec 12, 2022 at 14:46 comment added Chris Leary @Gerry Myerson - I was wondering if it came down to strictly a sum, with no subtractions. Thanks for clarifying.
Dec 10, 2022 at 22:08 comment added Gerry Myerson @Chris, there's a difference between a sum and a difference.
Dec 10, 2022 at 19:24 comment added Chris Leary @user2529 - I am confused by the terminology "sum of squares." If we think of Motzkin's example as a polynomial with real coefficients, aren't each of the monomial terms squares. Please enlighten me as to where my confusion lies.
Dec 10, 2022 at 17:23 history edited LSpice CC BY-SA 4.0
Capitalise title, while this is on the front page
Dec 10, 2022 at 12:10 history edited YCor CC BY-SA 4.0
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Mar 9, 2011 at 5:30 history edited user2529 CC BY-SA 2.5
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Feb 2, 2011 at 14:05 history edited user2529 CC BY-SA 2.5
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Feb 2, 2011 at 14:00 vote accept CommunityBot
Feb 2, 2011 at 14:00 history bounty ended CommunityBot
Jan 31, 2011 at 15:04 answer added J.C. Ottem timeline score: 18
Jan 28, 2011 at 21:45 answer added Bruce Reznick timeline score: 17
Jan 28, 2011 at 3:27 history edited user2529 CC BY-SA 2.5
edited title
Jan 27, 2011 at 6:18 answer added Gjergji Zaimi timeline score: 10
Jan 27, 2011 at 4:58 comment added user2529 this still leaves open as to whether a high power of Motzkin's power is a potential answer to my question.
Jan 27, 2011 at 4:43 comment added user2529 Hi JSE. The proof of that Motzkin's polynomial is not a sum of squares that I know is given by Reznick. This proof is almost brute force. Since the given polynomial is of low degree (deg 6) so the brute force method works. However, raising to high power makes such brute force method difficult.
Jan 27, 2011 at 4:39 comment added JSE Does Motzkin's proof that his f is not a sum of squares also show that f^N is not a sum of squares for odd N? Or could his polynomial itself already a potential positive answer to your question?
Jan 27, 2011 at 4:08 history bounty started CommunityBot
Jan 24, 2011 at 12:08 history edited Franz Lemmermeyer CC BY-SA 2.5
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Jan 24, 2011 at 12:04 history asked user2529 CC BY-SA 2.5