Michiel Hazewinkel

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Let A be a bipartite graph between two sets D and T. Then A defines by Hamming distance, metrics on both T and D. The question is studied which pairs of metric spaces can arise this way. If both spaces are trivial the matrix A comes from a Hadamard matrix or is a BIBD. The second question studied is in what ways A can be used to transfer (classification)(More)
Let NSymm be the Hopf algebra of non-commutative symmetric functions (in an infinity of indeterminates): NSymm=Z 12 , ,... ZZ . It is shown that an associative algebra A with a Hasse-Schmidt derivation 12 NSymm module algebra. The primitives of NSymm act as ordinary derivations. There are many formulas for the generators Z i in terms of the primitives(More)
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