Near the three equivalent L-points, there are three identical electron pockets (electron FS ellipsoids arrayed symmetrically around the hole FS with a small tilted angle (~6.5[degrees]) out of the plane defined by the bisectrix
and binary axes).
Since the function y[phi](y) is strictly increasing (one has that the derivative [phi](y) + y [phi]'(y) > 0) any critical point lies on the bisectrix
[x.sub.1] = [x.sub.2].
At the same time the vector group rotates about the bisectrix
of the vector pair.
The stochastic process (Bt , Bt) t>o is often called a planar Brownian motion reflected at a line (here the first bisectrix
Without taking the leakage flow over the screw flights into account, and with other geometrical assumptions, by assuming that the bank of material at the leading flight edge is approximately symmetrical with respect to the bisectrix
, and that the screw flank contacting the bank of material is reasonably flat, the axial velocity component is (12):
This position is given respectively when the bisectrix
between incoming and reflected light rays stands perpendicular to the crystal face.