Dualresonance models are treated both as Smatrix theories and as systems of interacting strings. We show how Veneziano was able to construct a dual fourpoint amplitude with narrow resonances and rising Regge trajectories. The construction is generalized to the JVpoint amplitude in the manifestly dual manner suggested by Koba and Nielsen. We develop the operator formalism which exhibits the factorization property of the above amplitude. The related questions of ghost elimination and null states are discussed. Models with extra degrees of freedom and, in particular, the NeveuSchwarzRamond model with spin, are treated. The latter model has a quarkline spectrum of mesons, but it possesses massless vector mesons and fermions. It is shown how the operator formalism is related to a quantized string. The theory of such a string is developed, with particular emphasis on the ghostfree "Coulombgauge" quantization. By constructing theories of interacting strings, we reproduce the dualmodel 5matrix. A brief account is given of the theory of loops, in which one attempts to improve on the narrowresonance model in a perturbative manner.

Authors: Mandelstam L. I.  Pages: 95 Year: 1974 
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