In PET studies testing blood flow to the human brain, Worsley et.
In PET studies testing blood flow to the human brain, Worsley et. al used this value as an estimator for the number of activated regions. This quantity can be determined in the situation where one surface is covering another by using a ramification index. Another theorem for determining this quantity can be proven by showing that the degree of a vector field equals its Lefschetz number. That theorem sets it equal to the sum of the indices over the zeroes of a vector space. Those are the Riemann-Hurwitz formula and the Poincare-Hopf index theorem. This quantity is equal to two minus twice the genus and it equals minus two for a double torus. For 10 points, name this quantity from topology which, for a polyhedron, equals verticies plus faces minus edges.
In PET studies testing blood flow to the human brain, Worsley et.
Euler characteristic