Kervaire semi-characteristic
In mathematics, the Kervaire semi-characteristic, introduced by , is an invariant of closed manifolds M of dimension  taking values in , given by 

. showed that the Kervaire semi-characteristic of a differentiable manifold is given by the index of a skew-adjoint elliptic operator. Assuming M is oriented, the Atiyah vanishing theorem states that if M has two linearly independent vector fields, then . References

Notes

Differential topology