On the computation of the gap metric

The author considers the gap metric introduced by G. Zames and A.K. El-Sakkary (1980). He derives an expression for the gap metric that is computable using well-known techniques from interpolation theory. The author also derives an alternate proof that the graph and the gap matrices are equivalent. This gives rise to upper and lower bounds for the graph metric, which is difficult to evaluate exactly.<<ETX>>