Adding stubs to quantum string field theories

Generalizing recent work by Schnabl-Stettinger and Erbin-Fırat, we outline a universal algebraic procedure for ‘adding stubs’ to string field theories obeying the BV quantum master equation. We apply our results to classical and quantum closed string field theory as well as to open-closed string field theory. We also clarify several aspects of the integration-out process in the co-algebraic formulation of string field theory at the quantum level.