Geometrising the closed string field theory action

Abstract

We complete the set of string vertices of non-negative dimension by introducing in a consistent manner those moduli spaces which had previously been excluded. As a consequence we obtain a `geometrised' string action taking the simple form $S=f(\B)$ where `$\B$' is the sum of the string vertices. That the action satisfies the B-V master equation follows from the recursion relations for the string vertices which take the form of a `geometrical' quantum master equation.