The generalN-point vertex in a dual model

Pinching parameters for open (super) strings

“…(A. 16) can be expressed in terms of multipliers, which can ultimately be expressed in terms of pinching parameters depending on the geometry of the graph Γ, thanks to the results of section A.1.…”

“…(A. 16), where k iαj ᾱ ≡ k(γ i γ α γ j γ −1 α ) and so on, and we have used the fact that k αj ᾱ = k j .…”

“…The benefits of using Schottky groups for stringinspired QFT calculations were laid out in [14]. Schottky groups had arisen as a parametrization of the moduli space of multi-loop string worldsheets in the earliest days of string theory, emerging automatically from an approach to amplitudes based on sewing together string interaction vertices [15][16][17][18][19][20]. The use of Schottky groups in string theory was put on a surer footing in the 1980's with the use of methods such as BRST quantization [21][22][23][24][25], conformal field theory [26] and the 'group theoretic approach' [27,28], and a super-geometric extension of Schottky groups [29] allowed the analysis to be generalized to the Neveu-Schwarz (NS) sector of the superstring.…”

One the Multi-Reggeon Vertex

“…The expressions of Kosterlitz and Wray, 6 ) and of Loh-ping Yu 7 ) will be examined in § § 2 and 3, respectively, and their connection with the expression derived by Lovelace 2 ) will there by be clarified. Before turning to our main subject, we should mention that we exploit a definition somewhat different from Lovelace's in the treatment of the zeroth mode.…”

“…Asymmetric and symmetric 3-reggeon vertices and 4-reggeon vertex were derived by Sciuto, 3 ) Caneschi and Schwimmer, 4 ) and Carbone and Sciuto,5 ) respectively. The procedure was extended to the case of the symmetric N-reggeon vertex by Kosterlitz and Wray,6 ) and Loh-ping Yu. 7 ) However the connection between these expressions and the one obtained by Lovelace was not clear.…”