Fixed-degree kernels over a number field
Determine which rational polygons P have a nonempty K-coefficient arithmetic kernel Ker_d(P,K) for a fixed number field K and degree bound d; determine whether the number of vertices or reflex vertices can bound a sufficient degree, and compare this kernel with the set of rational guards that see every real point of P along real-coefficient carriers of degree at most d.
References
Problem 10.2 (Fixed-degree kernels over a number field). Which rational polygons have nonempty Kerd(P, K)? For fixed K, can the number of vertices or reflex vertices bound a sufficient degree? How does this kernel compare with the set of rational guards that see every real point of P along real-coefficient carriers of degree at most d?
Problem 10.5 (Singularities and admissible sight arcs). For the same arithmetic gallery, compare guard numbers for absolutely irreducible carriers under four rules: (i) the entire affine carrier is nonsingular; (ii) the sight arc avoids singularities, as here; (iii) the sight arc lifts continuously to the real normalization; (iv) connected full traces permit branch switching at singularities. How large can the differences be, and what budget increase replaces singular sight by regular sight?
Whether the same guard sees every quadratic point of the upper arm on a rational conic remains a further question; see Problem 10.2.