Is this Polynomial an SOS Polynomial?

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In summary, an SOS polynomial is a polynomial that can be expressed as a sum of squares of other polynomials with non-negative coefficients. This type of polynomial is determined using the SOS decomposition method and has many benefits, including being easier to optimize, having a clear representation, and being useful in various fields. However, not all polynomials can be expressed as SOS polynomials and there are limitations, such as computational expense and certain optimization problems not being solvable using SOS polynomials.
  • #1
karate
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F = -0.2662*x^6 + 48.19*x^5 - 3424.2*x^4 + 121708*x^3 - 2*e^6*x^2 + 2*e^7*x - 6*e^7;
 
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  • #2
As mentioned in your other thread, ##\lim_{x\rightarrow\pm\infty}F(x)=-\infty##. So ##F## is sometimes (you could even say way more often than not) negative. Since a sum of squares is always nonnegative, your polynomial is not a sum of squares.
 
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  • #3
thank you sir, so what do you think is this type of equation?
 
  • #4
karate said:
thank you sir, so what do you think is this type of equation?

Well, first off the thing that (I think) you're asking me about is a function, not an equation. Secondly, I would characterize it as a polynomial of degree six.

Edit: I would also characterize this polynomial as apparently not being particularly well-suited for examination by analytic means.
 
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  • #5


Based on the given polynomial, it is not an SOS (Sum of Squares) polynomial. SOS polynomials have only non-negative coefficients, whereas this polynomial has negative coefficients. Additionally, SOS polynomials have a specific structure that is not present in this polynomial. Therefore, this is not an SOS polynomial.
 

1. What is an SOS polynomial?

An SOS (sum of squares) polynomial is a polynomial that can be expressed as a sum of squares of other polynomials, with all coefficients being non-negative. This type of polynomial is often used in optimization problems and has many applications in mathematics and engineering.

2. How do you determine if a polynomial is an SOS polynomial?

To determine if a polynomial is an SOS polynomial, one can use the SOS decomposition method. This involves expressing the polynomial as a sum of squares of other polynomials, and then using a mathematical proof called the Positivstellensatz to show that all coefficients are non-negative.

3. What are the benefits of using SOS polynomials?

SOS polynomials have several benefits, including being easier to optimize compared to general polynomials, having a clear and concise representation, and being useful in solving many real-world problems in various fields such as control theory, signal processing, and statistics.

4. Can all polynomials be expressed as SOS polynomials?

No, not all polynomials can be expressed as SOS polynomials. The polynomial must satisfy certain conditions, such as having a positive definite Hessian matrix, in order to be expressed as an SOS polynomial. However, many common types of polynomials, such as quadratic and cubic polynomials, can be expressed as SOS polynomials.

5. Are there any limitations to using SOS polynomials?

One limitation of using SOS polynomials is that the SOS decomposition method can be computationally expensive for polynomials with a large number of variables or a high degree. Additionally, not all optimization problems can be solved using SOS polynomials, as they may not have a suitable SOS decomposition.

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