# Paulina Rowińska - What Is a Manifold (Highlights)  ## Highlights - Albert Einstein used them in his general theory of relativity, bringing them out of the realm of philosophical abstraction and into the real world. ([View Highlight](https://read.readwise.io/read/01k9h5mprrwwc8qd6m1kwb5dme)) ^955418318 Manifold - Riemann had introduced a concept that could encompass all possible geometries, in any number of dimensions. A concept that would change how mathematicians view space. ([View Highlight](https://read.readwise.io/read/01k9h5n8yxf2a2bzm2sch23ct7)) ^955418325 Manifold - A manifold is a space that looks Euclidean when you zoom in on any one of its points. For instance, a circle is a one-dimensional manifold. ([View Highlight](https://read.readwise.io/read/01k9h5pt3p5y5q2ypn1hq7v856)) ^955418348 - In his general theory of relativity, Einstein described space-time as a four-dimensional manifold, and gravity as that manifold’s curvature. ([View Highlight](https://read.readwise.io/read/01k9h5wyqg9z7980qrf7wvm6db)) ^955418658