  We consider snap-stabilizing algorithms in anonymous networks.
Self-stabilizing algorithms are well known fault tolerant algorithms : a
self-stabilizing algorithm will eventually recover from arbitrary transient
faults. On the other hand, an algorithm is snap-stabilizing if it can withstand
arbitrary initial values and immediately satisfy its safety requirement. It is
a subset of self-stabilizing algorithms. Distributed tasks that are solvable
with self-stabilizing algorithms in anonymous networks have already been
characterized by Boldi and Vigna in [BV02b]. In this paper, we show how the
more demanding snap-stabilizing algorithms can be handled with standard tools
for (not stabilizing) algorithms in anonymous networks. We give a
characterization of which tasks are solvable by snap-stabilizing algorithms in
anonymous networks. We also present a snap-stabilizing version of Mazurkiewicz'
enumeration algorithm. This work exposes, from a task-equivalence point of
view, the complete correspondence in anonymous networks between self or
snap-stabilizing tasks and distributed tasks with various termination detection
requirements.
