Hyperkähler manifold

A Hyperkähler manifold is a special type of Riemannian manifold that has a rich geometric structure. It is characterized by several key properties: 1. **Riemannian Manifold**: A Hyperkähler manifold is a Riemannian manifold, meaning it is equipped with a Riemannian metric that allows the measurement of distances and angles. 2. **Complex Structure**: It possesses a complex structure, which means that it can be viewed as a complex manifold.