Based on five different mappings of a function on a circle (i.e. a periodic function) to a function on a line or a line segment (i.e. a non-periodic function), measures for the width of a periodic function (expressed in terms of centered second-order moments) are defined, and the associated uncertainty-type relationships are derived, using a generalized version of the Cauchy-Schwarz inequality.

To: Papers by Martin J. Bastiaans