TwoForm - crowlogic/arb4j GitHub Wiki

A 2-form is a differential 2-form, which is a smooth, alternating, and multilinear map that takes two tangent vectors and returns a scalar. It's a generalization of the notion of a surface element in Euclidean space.

A 2-form w is closed if its exterior derivative, dw, is zero. The ExteriorDerivative is an operation that generalizes the concept of a differential in calculus.

A 2-form w is non-degenerate if, for every non-zero tangent vector v at a point in the manifold, there exists another tangent vector w such that w(v, w) = / 0.