Assume $p$ and $q$ are n-variate degree d, homogeneous polynomials. Define $ |p|_{\infty}= \max_{x \in S^{n-1}} |p(x)|$ 
$D(p)=\{ x \in R^n : p(x)= |p|_{\infty} \}$  
$E(p)=\{x \in R^n : p(x)= -|p|_{\infty} \}$   

Define $D(q)$ and $E(q)$ similarly. Now assume $ D(p) \cup E(p) = D(q) \cup E(q) $ 
What kind of relation we can deduce between $p$ and $q$ by this assumption?