  The envelope theory is a simple technique to obtain approximate, but
reliable, solutions of many-body systems with identical particles. The accuracy
of this method is tested here for two systems in one dimension with pairwise
forces. The first one is the fermionic ground state of the analytical Calogero
model with linear forces supplemented by inverse-cube forces. The second one is
the ground state of up to 100 bosons interacting via a Gaussian potential. Good
bounds can be obtained depending on values of the model parameters.
