  We explicitly show that, in a system with T-duality symmetry, the
configuration space volume degrees of freedom may hide on the surface boundary
of the region of accessible states with energy lower than a fixed value. This
means that, when taking the decompactification limit (big volume limit), a
number of accessible states proportional to the volume is recovered even if no
volume dependence appears when energy is high enough. All this behavior is
contained in the exact way of computing sums by making integrals. We will also
show how the decompactification limit for the gas of strings can be defined in
a microcanonical description at finite volume.

High Energy Physics - Theory