Gauge invariance of Banks-Peskin differential forms (flat background) (Q915220)

The author debates upon some aspects of the gauge invariance of Banks- Peskin differential forms on a flat background. In this paper, which is a sequel of two other works of the author [``The representation theory and applications of groups in physics'', Proc. 4-th Russ. Semin., Tambov (1989) and Lett. Math. Phys. (to be published)] the author presents a very modern method for separating the variables which are characterized as external and internal degrees of freedom of a closed string. This method leads to a string mathematical theory for closed string fields realizing these fields not as differential forms but as sections of a fibre bundle, and the BRST operator is regarded not as a partial differential along the constraint foliation but as a covariant one in the bundle. This article is written in a very logic manner, the fundamental steps and the new notions are comprehensible introduced so it might be a pleasure for mathematicians to read it.