Schematic
illustrations of a defective clique and how the concept evolved. (**A**)
A defective clique in a protein interaction network. *KP*
and *KQ*
are both (*k* +
*1*)-cliques,
with *k*
overlapping vertices (i.e. clique *K*).
The dashed edge between proteins *P*
and *Q*
corresponds to a predicted interaction. *KPQ*
is a defective clique with a missing edge *PQ*. (**B**)
The decomposition of the defective clique (*KPQ*)
into the union of two overlapping cliques (*KP*
and *KQ*).
(**C**)
Generalized defective cliques. In general, a defective clique consists
of two cliques: *K* *K*_{P}
and *K* *K*_{Q}.
There are two parameters to determine a defective clique: *k*,
the size of the overlapping subclique (i.e. *K*);
*l*,
the size of the non-overlapping subcliques (i.e. *K*_{P} *K*_{Q}).
In the defective clique *K* *K*_{P} *K*_{Q},
the dashed edges between subcliques *K*_{P}
and *K*_{Q} correspond to predicted interactions. [from H. Yu, A. Paccanaro, V. Trifonov, M.
Gerstein (2006). *Predicting
interactions in protein networks
by completing defective cliques*.
Bioinformatics 2006 Apr 1;22(7):823-9]