diff --git a/report/report.tex b/report/report.tex
index 08ca616..d9e46eb 100644
--- a/report/report.tex
+++ b/report/report.tex
@@ -409,7 +409,11 @@ and an isomorphism has been found; if not, we move on to the next permutation.
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Pattern-match}
 
-\todo{}
+We finally need to be able to find every occurrence of a given \emph{needle}
+circuit in a bigger \emph{haystack} circuit — at any level in its groups
+hierarchy. This problem is basically graph isomorphism with some specificities,
+and for this purpose I used a classical algorithm for the subgraph isomorphism
+problem, \emph{Ullmann}.
 
 \subsection{Ullmann's algorithm}