Descent relations and the oscillator level-truncation method

We reexamine the oscillator level-truncation method in the bosonic string field theory by calculating the descent relation . We use the fermionic vertices in the standard oscillator basis for the ghost sector. We propose two new calculation schemes: in the first, we assume that the insertion satisfies the overlap equation for the vertices; in the second, we use direct calculations. In both schemes, we obtain the correct structures of the exponent and preexponent of the vertex 〈V₂|, but we find different normalization factors . __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 150, No. 1, pp. 5–25, January, 2007.