Kretschmann scalar

In the theory of Lorentzian manifolds, particularly in the context of applications to general relativity, the Kretschmann scalar is a quadratic scalar invariant. It was introduced by Erich Kretschmann. In the theory of Lorentzian manifolds, particularly in the context of applications to general relativity, the Kretschmann scalar is a quadratic scalar invariant. It was introduced by Erich Kretschmann. The Kretschmann invariant is where R a b c d {displaystyle R_{abcd}} is the Riemann curvature tensor. Because it is a sum of squares of tensor components, this is a quadratic invariant.