  We consider the tree-level amplitude, describing all 3 channels of the binary
(pi ,K)-reaction, as a meromorphic polynomially bounded function of 3 dependent
complex variables. Relying systematically on the Mittag-Leffler theorem, we
construct 3 convergent partial fraction expansions, each one being applied in
the corresponding domain. Noting, that the mutual intersections of those
domains are nonempty, we realize the analytical continuation. It is shown that
the necessary conditions to make such a continuation feasible, are the
following: 1) The only parameters completely determining the amplitude are the
on-shell couplings and masses; 2) These parameters are restricted by a certain
(infinite) system of bootstrap equations; 3) The full cross-symmetric amplitude
takes the typically dual form, the Pomeron contribution being taken into
account; 4)This latter contribution corresponds to a nonresonant background,
which, in turn, is expressed in terms of cross-channel resonances parameters.
It is demonstrated also, that the Chiral Symmetry provides a unique scale for
the mentioned parameters, the resonance saturation effect appearing as a direct
consequence of the above results.
