  We study fluctuations in the canonical ensemble, where the net baryon number
is exactly conserved. The focus is on cumulants and factorial cumulants linked
to the baryon and antibaryon multiplicities and their sum or difference in full
phase-space as well as in subsystems. In particular, we connect the
fluctuations of the net baryon number in a subsystem, relevant for fluctuation
studies in nucleus-nucleus collisions, with fluctuations of the baryon and
antibaryon numbers of the total system. We derive analytic expressions for
factorial cumulants of arbitrary order. Compact results are obtained in terms
of cumulants of the baryon number of the total system. Moreover, we derive the
asymptotic forms of the factorial cumulants of baryon and antibaryon
multiplicities in the high- and low-temperature limits and discuss the results
in the context of heavy-ion collision experiments.
