diff --git a/compiler/heptagon/analysis/causal.ml b/compiler/heptagon/analysis/causal.ml
index 9dd729b..598cd9f 100644
--- a/compiler/heptagon/analysis/causal.ml
+++ b/compiler/heptagon/analysis/causal.ml
@@ -14,7 +14,7 @@ open Names
 open Idents
 open Heptagon
 open Location
-open Graph
+open Sgraph
 open Format
 open Pp_tools
 
diff --git a/compiler/heptagon/analysis/causality.ml b/compiler/heptagon/analysis/causality.ml
index cc6bb8b..58ea744 100644
--- a/compiler/heptagon/analysis/causality.ml
+++ b/compiler/heptagon/analysis/causality.ml
@@ -14,7 +14,7 @@ open Names
 open Idents
 open Heptagon
 open Location
-open Graph
+open Sgraph
 open Causal
 
 let cempty = Cempty
diff --git a/compiler/minils/transformations/schedule.ml b/compiler/minils/transformations/schedule.ml
index 87ed04d..aa77b7f 100644
--- a/compiler/minils/transformations/schedule.ml
+++ b/compiler/minils/transformations/schedule.ml
@@ -12,7 +12,7 @@
 open Misc
 open Minils
 open Mls_utils
-open Graph
+open Sgraph
 open Dep
 
 (* possible overlapping between clocks *)
diff --git a/compiler/utilities/global/dep.ml b/compiler/utilities/global/dep.ml
index 268f963..786a7c7 100644
--- a/compiler/utilities/global/dep.ml
+++ b/compiler/utilities/global/dep.ml
@@ -8,7 +8,7 @@
 (**************************************************************************)
 (* dependences between equations *)
 
-open Graph
+open Sgraph
 open Idents
 
 module type READ =
diff --git a/compiler/utilities/graph.ml b/compiler/utilities/sgraph.ml
similarity index 100%
rename from compiler/utilities/graph.ml
rename to compiler/utilities/sgraph.ml