Let G be a finite group. A family M of maximal subgroups of G
is called `irredundant' if its intersection is not equal to the intersection of
any proper subfamily. M is called `maximal irredundant' if
M is irredundant and it is not properly contained in any other
irredundant family. We denote by \mbox{Mindim}(G) the minimal size of a
maximal irredundant family of G. In this paper we compute \mbox{Mindim}(G)
when G is the alternating group on n letters