A Wolf space is a compact, simply connected, irreducible quaternion-Kähler symmetric space of positive dimension. Equivalently,
it is a homogeneous space 
whose isotropy group has a distinguished factor locally
isomorphic to 
and whose holonomy is contained in 
.
The quaternionic projective spaces are Wolf spaces. Additional examples arise from each compact simple Lie group and include quaternionic Grassmannians and exceptional homogeneous spaces.
