Comment about UV regularization of basic commutators in string theories
  Recently proposed by Hwang, Marnelius and Saltsidis zeta regularization of basic commutators in string theories is generalized to the string models with non-trivial vacuums. It is shown that implementation of this regularization implies the cancellation of dangerous terms in the commutators between Virasoro generators, which break Jacobi identity. 
A.Yu. Kamenshchik, I.M. Khalatnikov (Landau Institute for Theoretical   Physics, Moscow), M. Martellini (University of Milan)