The abelianity conjecture for special compact Kähler manifolds asserts that their fundamental groups are virtually Abelian. This means that the entire discrete
group contains an Abelian subgroup of finite index,
equivalently that the manifold has a connected finite
unramified holomorphic cover with Abelian fundamental
group.
Campana, F. and Claudon, B. "Abelianity Conjecture for Special Compact Kähler 3-Folds." Proc. Edinb. Math. Soc.57,
55-78, 2014. https://doi.org/10.1017/S0013091513000849.Cao,
J.; Deng, Y.; Hacon, C. D.; and Păun, M. "Two-Step Nilpotent Monodromy
of Local Systems on Special Varieties." 7 Apr 2026. https://arxiv.org/abs/2603.14539v2.