On pseudo-real finite subgroups of $\operatorname{PGL}_3(\mathbb{C})$
Abstract
Let be a finite subgroup of , and let be the generator of . We say that has a \emph{real field of moduli} if and are -conjugates, that is, if such that . Furthermore, we say that is \emph{a field of definition for } or that \emph{ is definable over } if is -conjugate to some . In this situation, we call \emph{a model for over }. If has as a field of definition but is not definable over , then we call \emph{pseudo-real}. In this paper, we first show that any finite cyclic subgroup in has {a real field of moduli} and we provide a necessary and sufficient condition for to be definable over ; see Theorems 2.1, 2.2, and 2.3. We also prove that any dihedral group with in is definable over ; see Theorem 2.4. Furthermore, we study all six classes of finite primitive subgroups of , and show that all of them except the icosahedral group are pseudo-real; see Theorem 2.5, whereas is definable over . Finally, we explore the connection of these notions in group theory with their analogues in arithmetic geometry; see Theorem 2.6 and Example 2.7.
Keywords
Cite
@article{arxiv.2301.00543,
title = {On pseudo-real finite subgroups of $\operatorname{PGL}_3(\mathbb{C})$},
author = {Eslam Badr and Ahmad El-Guindy},
journal= {arXiv preprint arXiv:2301.00543},
year = {2023}
}
Comments
11 pages