Yau's Theorem, formulated by mathematician Shing-Tung Yau, is a significant result in the field of differential geometry. It states that under certain conditions, a compact Riemannian manifold can be deformed to have a metric with constant scalar curvature. This theorem has important implications for the study of geometric structures and the topology of manifolds. The theorem is particularly relevant in the context of Kähler manifolds, which are complex manifolds with a compatible Riemannian metric. Yau's work has influenced various areas of mathematics and theoretical physics, including string theory and the study of Einstein manifolds.