  I abstract from a recent publication [1] the motivations for, analysis in and
conclusions of a study of the ultraviolet and infrared momentum regulators
induced by the necessary truncation of the model spaces formed by a variational
trial wave function. This trial function is built systematically from a
complete set of many-body basis states based upon three-dimensional harmonic
oscillator (HO) functions. Each model space is defined by a truncation of the
expansion characterized by a counting number (N) and by the intrinsic scale
($\hbar\omega$) of the HO basis. Extending both the uv cutoff to infinity and
the ir cutoff to zero is prescribed for a converged calculation. In [1] we
established practical procedures which utilize these regulators to obtain the
extrapolated result from sequences of calculations with model spaces. Finally,
I update this subject by mentioning recent work on our extrapolation
prescriptions which have appeared since the submission of [1]. The numerical
example chosen for this contribution consists of calculations of the ground
state energy of the triton with the "bare" and "soft" Idaho N3LO
nucleon-nucleon (NN) interaction.
