Let X be a symmetric space of noncompact type whose isometry group is either SU(n, 1) or Spin(2n, 1). Then the Dirac operator D is defined on L2-sections of certain homogeneous vector bundles over X.

In 1972, Olympus changed the face of 35mm single lens reflex (SLR) photography with the introduction of the OM-1 which, in the words of its advertising blurb, was ‘smaller, lighter, tougher, quieter, ...