We investigate language contact effects between Bulgarian dialects on the one hand, and the languages of the countries bordering Bulgaria on the other. The Bulgarian data comes from Stojkov's Bulgarian Dialect Atlases. We investigate three techniques to detect contact effects in pronunciation, the phone frequency method and the feature frequency method, both of which are insensitive to the orde...

Based on the Delsarte-Yudin linear programming approach, we extend Levenshtein’s framework to obtain lower bounds for minimum $h$-energy of spherical codes prescribed dimension and cardinality, upper maximal cardinality separation. These are universal in sense that they hold a large class potentials $h$ Levenshtein. Moreover, attaining universally optimal Cohn-Kumar. Referring Levenshtein ene...

We develop refinements of the Levenshtein bound in q-ary Hamming spaces by taking into account the discrete nature of the distances versus the continuous behavior of certain parameters used by Levenshtein. The first relevant cases are investigated in detail and new bounds are presented. In particular, we derive generalizations and q-ary analogs of a MacEliece bound. We provide evidence that our...

Codebooks with small inner-product correlation are applied in many practical applications including direct spread code division multiple access communications, space-time codes and compressed sensing. It is extremely difficult to construct codebooks achieving the Welch or Levenshtein bound. In this paper, we firstly generalize Jacobi sums over finite fields and secondly obtain asymptotically op...