  A light beam with phase singularity (PS) characterized with azimuthally
symmetric angular positions (APs) can be constructed by the rotationally
symmetric superposition of n (n is N) fractional vortex light beams with
identical charges. The profile of this light beam deforms after propagation
owing to its orbital angular momentum (OAM) noneigenvalue, and the deformation
degree can be evaluated by the degree of phase dislocation associated with the
PS. The expectation value of the mean deviation of its OAM from its
characteristic charge value and the variation of the degree of phase
dislocation obey a proportional relation. This light beam offers a quantifiable
example of a complementarity relation between the observers of optical OAM and
AP, which are the OAM noneigenvalue and intensity AP variation, respectively.
