  This letter investigates the application of the emerging fluid antenna (FA)
technology in multiuser communication systems when side information (SI) is
available at the transmitters. In particular, we consider a K-user dirty
multiple access channel (DMAC) with non-causally known SI at the transmitters,
where K users send independent messages to a common receiver with a FA capable
of changing its location depending on the channel condition. By connecting
Jakes' model to copula theory through Spearman's {\rho} rank correlation
coefficient, we accurately describe the spatial correlation between the FA
channels, and derive a closed-form expression for the outage probability (OP)
under Fisher-Snedecor F fading. Numerical results illustrate how considering FA
can improve the performance of multiuser communication systems in terms of the
OP and also support a large number of users using only one FA at the common
receiver in a few wavelengths of space.
