================================================================================ P9325 J.C.M. Baeten & J.A. Bergstra "Real time process algebra with infinitesimals" We consider a model of the real time process algebra of [BaB91,93,92] based on the nonstandard reals. As a subalgebra, we obtain a theory in which the urgent actions of ATP, TiCCS, TeCCS can be modeled. [BaB91] J.C.M. Baeten & J.A. Bergstra, Real time process algebra, Formal Aspects of Computing 3(2), 1991, pp. 142-188. [BaB92] J.C.M. Baeten & J.A. Bergstra, Discrete time process algebra, in Proc. CONCUR'92, Stony Brook, NY (W.R. Cleaveland, ed.), Springer LNCS 630, 1992, pp. 401-420. [BaB93] J.C.M. Baeten & J.A. Bergstra, Real space process algebra, Formal Aspects of Computing 5(6), 1991.