Some Metrical Problems on S "
نویسندگان
چکیده
We present some problems related to right(or bi-)invariant metrics d on the symmetric group of permutations S,. Characterizations and constructions of bi-invariant extremal (in the corresponding convex cone) metrics are given, esp. for n 6 5 . We also consider special subspaces of the metric space (S,,, d ) : unit balls, sets with prescribed distances (L-cliques), "hamiltonian" sets. Here we give (for proofs, see [ 3 ] ) some results and problems arising by analogy with extremal set systems. Related problems of coding type (with Hamming metric) are considered in [l , 41.
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