Nearly Kähler manifold

A Nearly Kähler manifold is a specific type of almost Kähler manifold, which is a manifold equipped with a Riemannian metric and a compatible almost complex structure. More formally, if \( M \) is a manifold, it is said to be nearly Kähler if it possesses the following structures: 1. **Riemannian Metric**: A Riemannian metric \( g \) on \( M \), which provides a way to measure distances and angles.