Vertical Integration from the Large Hilbert Space

TL;DR

This paper introduces a new approach to vertical integration in string theory using BRST exact amplitudes in the large Hilbert space, connecting it to existing methods by Sen and Witten.

Contribution

It presents an alternative formulation of vertical integration based on BRST exactness, offering a novel perspective in the large Hilbert space framework.

Findings

Provides a new mathematical description of vertical integration.

Establishes a connection between BRST exact amplitudes and existing vertical integration methods.

Enhances understanding of the large Hilbert space approach in string theory.

Abstract

We develop an alternative description of the procedure of vertical integration based on the observation that amplitudes can be written in BRST exact form in the large Hilbert space. We relate this approach to the description of vertical integration given by Sen and Witten.