Complex sentence: Klein theory used the fifth dimension to unify gravity with the electromagnetic force; e.g. Minkowski space and Maxwell's equations in vacuum can be embedded in a five-dimensional Riemann curvature tensor.
Split into simpler sentences: Klein theory used the fifth dimension to unify gravity with the electromagnetic force. For example, Minkowski space and Maxwell's equations in vacuum can be embedded in a five-dimensional Riemann curvature tensor.