Regge behavior, crossing symmetry, and unitarity in the Nakanishi representation

The analyticity of the weight function ψ in the Nakanishi representation is discussed under certain assumptions and a simple inversion formula is proved. Two-particle unitarity is formulated as an integral equation for ψ. A crossing-symmetric asymptotic form for ψ corresponding to Regge behavior for the amplitude is obtained. The significance of this investigation for the construction of dual amplitudes is discussed.