Green-Schwarz superstring in extended configuration space and the infinitely reducible first class constraints problem

The Green-Schwarz superstring action is modified to include some set of additional (on-shell trivial) variables. A complete constraint system of the theory turns out to be reducible both in the original and in additional variable sectors. The initial [Formula presented] first class constrainst and [Formula presented] second class ones are shown to be unified with [Formula presented] first class and [Formula presented] second class constraints from the additional variables sector, resulting in SO(1,9)-covariant and linearly independent constraint sets. Residual reducibility proves to fall on second class constraints only.