Overlapping Discs Filtration in the Commutative Operad
The spaces of configurations of non-$k$-overlapping discs have been studied as a bimodule over the little discs operad. In fact, the spaces form a filtered operad. We define and study the induced structure on the homology.
Concatenated optical coding provides channel grouping ability on OCDM networks. With the 16-chip optical code concatenating two 4-chip Fourier codes, selection of a channel in sixteen or a code group in four is experimentally demonstrated.