Kharitonov-like results in the space of Markov parameters

The largest stability box in the space of Markov parameters is determined. This result relies of Markov´s theorem of determinants which gives a stability test (for a family of polynomials) involving only two (vertex) polynomials. V.L. Kharitonov´s theorem (1978), which works for boxes in polynomial coefficient space, requires four polynomials to be stable