  In general there exists no relationship between the fixed point sets of the
composition and of the average of a family of nonexpansive operators in Hilbert
spaces. In this paper, we establish an asymptotic principle connecting the
cycles generated by under-relaxed compositions of nonexpansive operators to the
fixed points of the average of these operators. In the special case when the
operators are projectors onto closed convex sets, we prove a conjecture by De
Pierro which has so far been established only for projections onto affine
subspaces.
