1. A short review of previous results: an extended perturbative
scheme for a localizable effective theory of strong interaction;
reduction procedure and minimal parameters; minimal set of
renormalization prescription fixing physical contents of an
2. The method of Cauchy forms for functions of two variables
3. A test ground for our methods: Lovelace string amplitude (short
review of general properties); Cauchy forms for the string
4. The notion of duality revisited; bootstrap constraints for the
5. Numerical tests of sum rules that follow from the bootstrap system
for string-like amplitude.
6. Renormalization prescriptions fixing tree-level 4-leg vertices in
a realistic effective scattering theory.