  We investigate the behaviour of a three-phase composite, structured as a
hexagonal array of coated cylinders, when the sum of the dielectric constants
of the core and shell equals zero. In such cases, the absorption of the
composite is the same as the absorption of a periodic array of solid cylinders
of core material and radius equal to the outer radius of the original coated
cylinder. When the sum of the dielectric constants of the shell and matrix
equals zero, the composite has the same absorption as a periodic array of solid
cylinders of core material, and radius exceeding the shell radius.
