diff --git a/src/main/clojure/conexp/fca/contexts.clj b/src/main/clojure/conexp/fca/contexts.clj
index 1d7c558e..a4af4aa8 100644
--- a/src/main/clojure/conexp/fca/contexts.clj
+++ b/src/main/clojure/conexp/fca/contexts.clj
@@ -276,6 +276,16 @@
   (let [objs (aprime ctx #{m})]
     [objs (oprime ctx objs)]))
 
+(defn object-concepts [ctx]
+  "Returns a set of all object-concepts of the specified context."
+  (set (for [obj (objects ctx)] (object-concept ctx obj)))
+)
+
+(defn attribute-concepts [ctx]
+   "Returns a set of all attribute-concepts of the specified context."
+  (set (for [attr (attributes ctx)] (attribute-concept ctx attr)))
+)
+
 (defn clarify-objects
   "Clarifies objects in context ctx."
   [ctx]
diff --git a/src/main/clojure/conexp/fca/matrices.clj b/src/main/clojure/conexp/fca/matrices.clj
index 455e0118..abeeee9d 100644
--- a/src/main/clojure/conexp/fca/matrices.clj
+++ b/src/main/clojure/conexp/fca/matrices.clj
@@ -92,3 +92,9 @@
     (into [] (for [c (range (col-number M1))]
                (* ((M1 r) c) ((M2 r) c))))))
 )
+
+(defn outer-prod [v1 v2]
+  "Computes the outer product of two vectors."
+  (into [] (for [x v1]
+    (into [] (for [y v2] (* x y)))))
+)
diff --git a/src/main/clojure/conexp/fca/matrix_factorizations.clj b/src/main/clojure/conexp/fca/matrix_factorizations.clj
index 7696da3f..047a1ac6 100644
--- a/src/main/clojure/conexp/fca/matrix_factorizations.clj
+++ b/src/main/clojure/conexp/fca/matrix_factorizations.clj
@@ -260,12 +260,6 @@
 ;; https://doi.org/10.1137/1.9781611972801.15
 ;; Compare Algorithm 1
 
-(defn outer-prod [v1 v2]
-  "Computes the outer product of two vectors."
-  (into [] (for [x v1]
-    (into [] (for [y v2] (* x y)))))
-)
-
 (defn- cost [patterns ctx]
   "computes the cost function of the given patterns.
    Compare Problem 1"
@@ -399,17 +393,6 @@
 ;; https://doi.org/10.1016/j.jcss.2009.05.002
 ;; Compare Algorithm 1
 
-(defn object-concepts [ctx]
-  "Returns a set of all object-concepts of the specified context."
-  (set (for [obj (objects ctx)] (object-concept ctx obj)))
-)
-
-(defn attribute-concepts [ctx]
-   "Returns a set of all attribute-concepts of the specified context."
-  (set (for [attr (attributes ctx)] (attribute-concept ctx attr)))
-)
-
-
 (defn- mandatory-factors [ctx]
   "Computes the concepts that are both object-concepts and attribute-concepts 
    and removes them from the incidence relation. These concepts are required