Orbits and Fields of Definition for Graded Keller Maps

Abstract

We classify graded Keller maps by the signature of their weight vectors and address which hyperbolic weights support counterexamples and how the nonempty loci are stratified. We construct two families. Cyclic cones populate \(K(3,(1,-1,-1))\) at every composite generic fibre degree \(N\geq 6\), including a six-sheeted member over \(\mathbb{Q}(\sqrt{-15})\) and a 33-sheeted member over \(\mathbb{Q}\). A diagonal family gives \(K(3,(1,-p,-p))\neq\varnothing\) for every \(p\geq2\), with \(\det JF_p=-p\) and generic fibre degree \(2p-1\). The geometric monodromy of every member of both families is alternating or symmetric of full degree; hence the solvable case occurs only in generic degree three. At generic degree twelve, normalized quartic cyclic seeds form a smooth plane cubic over \(\mathbb{Q}\), whose points yield pairwise distinct graded-equivalence orbits. Thus the relevant orbit space contains a nonconstant algebraic family, establishing genuine moduli rather than isolated examples."