  Bipartite networks with exchangeable nodes can be represented by row-column
exchangeable matrices. A quadruplet is a submatrix of size $2 \times 2$. A
quadruplet $U$-statistic is the average of a function on a quadruplet over all
the quadruplets of a matrix. We prove several asymptotic results for quadruplet
$U$-statistics on row-column exchangeable matrices, including a weak
convergence result in the general case and a central limit theorem when the
matrix is also dissociated. These results are applied to statistical inference
in network analysis. We suggest a method to perform parameter estimation,
network comparison and motifs count for a particular family of row-column
exchangeable network models: the bipartite expected degree distribution (BEDD)
models. These applications are illustrated by simulations.
