The Ward identities of the W∞ symmetry in two-dimensional string theory in the tachyon background are studied in the continuum approach. We consider amplitudes different from 2D string ones by the external leg factor and derive the recursion relations among them. The recursion relations have non-linear terms which give relations among the amplitudes defined on different genus. The solutions agree with the matrix model results even in higher genus. We also discuss the differences of the roles of the external leg factor between the cM = 1 model and the cm < 1 model.
Nuclear Physics B
- Pub Date:
- February 1996
- High Energy Physics - Theory
- 21 pages, Latex, 5 figures. Revised version published in Nucl. Phys. B. Errors of coefficients in some formula and the potential term are corrected. Some sentences are rewritten