  We find for the unitary evolution of spin-1/2 systems that the "purely
mathematical mixed state holonomy of Uhlmann limitedly agrees, in the case of
evolution over geodesic spherical triangles, with the holonomy "in the
experimental context of quantum interferometry" recently proposed by Sjoqvist,
Pati, Ekert, Anandan, Ericsson, Oi and Vedral (Phys. Rev. Lett. 85 [2000],
2845-2848).
