A random-cluster model on a finite graph is a measure
on the measurable
space
defined as follows. Let
, whose elements are
vectors
, and let
be the sigma-algebra of
all subsets of
. For each
, set
|
(1)
|
where here,
and
are parameters,
is the so-called partition function
|
(2)
|
and
denotes the number of connected components
of the graph
where
|
(3)
|
The connected components of are called open clusters.
For a positive integer and
, the substitution
identifies
, up to the factor
, with the
-state Potts model partition
function.
In the above setting, the case corresponds to a model in which graph
edges are open (i.e.,
) or closed (i.e.,
) independently
of one another, a scenario which can be used as an alternative definition for the
term percolation. For
, edge states are generally
dependent, giving a model of dependent
percolation. On a forest, however,
, and edge
states are independent with open probability
.
For the critical model on the square integer lattice with
and
, Averous et al. (2026) reported convergence
of its loops in the scaling limit to the conformal
loop ensemble
.
The associated four-state Potts model consequently
has a conformally invariant scaling limit.