Optimal information dissemination in Star and Pancake networks

The paper presents a new decomposition technique for hierarchical Cayley graphs. This technique yields a very easy implementation of the divide and conquer paradigm for weak order problems on very complex architectures as the Star graph or the Pancake. As applications, we introduce asymptotically optimal algorithms for broadcasting, gossiping, and semigroup operations for such interconnection networks, improving the best known bounds for these problems.<<ETX>>