Journal of Statistical Physics, Vol. 40, Nos. 5/6, 1985. p. 631-653.
We study a one-dimensional gas of Bosons interacting through Neumann hard cores of diameter a. Attractive boundary conditions are imposed on the system, so that when a = 0 the model exhibits Bose-Einstein condensation and singular thermodynamic functions. In the presence of a hard core (a > 0), the free energy density retains its singularity, but Bose-Einstein condensation does not persist, even in the generalized sense.