diff --git a/src/rsprocess/grammar.lalrpop b/src/rsprocess/grammar.lalrpop
index 97d9dde..6870546 100644
--- a/src/rsprocess/grammar.lalrpop
+++ b/src/rsprocess/grammar.lalrpop
@@ -272,11 +272,20 @@ LiteralSeparatorEdge: presets::EdgeDisplay = {
 };
 
 NodeDisplay: presets::NodeDisplay = {
-    "Hide" => presets::NodeDisplay::Display(graph::GraphMapNodes::Hide),
-    "Entities" => presets::NodeDisplay::Display(graph::GraphMapNodes::Entities),
+    "Hide" =>
+	presets::NodeDisplay::Display(graph::GraphMapNodes::Hide),
+    "Entities" =>
+	presets::NodeDisplay::Display(graph::GraphMapNodes::Entities),
     "MaskEntities" <mask: Set> =>
 	presets::NodeDisplay::Display(graph::GraphMapNodes::MaskEntities{mask}),
-    "Context" => presets::NodeDisplay::Display(graph::GraphMapNodes::Context)
+    "Context" =>
+	presets::NodeDisplay::Display(graph::GraphMapNodes::Context),
+    "UncommonEntities" =>
+	presets::NodeDisplay::UncommonEntities,
+    "MaskUncommonentities" <mask: Set> =>
+	presets::NodeDisplay::MaskUncommonEntities(mask),
+    "ExcludeEntities" <mask: Set> =>
+      presets::NodeDisplay::Display(graph::GraphMapNodes::ExcludeEntities{mask})
 }
 
 /// Node display formatters separated by arbitrary strings in quotes
diff --git a/src/rsprocess/graph.rs b/src/rsprocess/graph.rs
index bf51f18..48ce5c6 100644
--- a/src/rsprocess/graph.rs
+++ b/src/rsprocess/graph.rs
@@ -41,6 +41,20 @@ pub fn digraph(
     Ok(graph)
 }
 
+
+pub fn common_entities(
+    graph: &RSgraph
+) -> RSset {
+    graph.node_references().fold(
+	None,
+	|acc, node|
+	match acc {
+	    None => Some(node.1.available_entities.clone()),
+	    Some(acc) => Some(node.1.available_entities.intersection(&acc))
+	}
+    ).unwrap_or(RSset::new())
+}
+
 // -----------------------------------------------------------------------------
 //                              helper functions
 // -----------------------------------------------------------------------------
@@ -54,6 +68,7 @@ pub enum GraphMapNodes {
     Hide,
     Entities,
     MaskEntities { mask: RSset },
+    ExcludeEntities { mask: RSset },
     Context,
 }
 
@@ -108,6 +123,20 @@ impl GraphMapNodesTy {
 			}
 		    )
 		},
+		ExcludeEntities { mask } => {
+		    Box::new(
+			move |_, node: &RSsystem| {
+			    let masked_entities =
+				node.available_entities
+				.subtraction(&mask);
+			    format!("{}",
+				    translator::RSsetDisplay::from(
+					&translator,
+					&masked_entities)
+			    )
+			}
+		    )
+		}
 		Context => {
 		    Box::new(
 			move |_, node: &RSsystem|
diff --git a/src/rsprocess/presets.rs b/src/rsprocess/presets.rs
index 7a859ae..70a3542 100644
--- a/src/rsprocess/presets.rs
+++ b/src/rsprocess/presets.rs
@@ -62,6 +62,8 @@ impl Default for SaveOptions {
 pub enum NodeDisplay {
     Separator(String),
     Display(graph::GraphMapNodes),
+    UncommonEntities,
+    MaskUncommonEntities(RSset)
 }
 
 
@@ -539,6 +541,7 @@ pub fn bisimilar(
 #[allow(clippy::type_complexity)]
 fn generate_node_pringting_fn<'a>(
     node_display: &'a Vec<NodeDisplay>,
+    graph: &graph::RSgraph,
     translator: Rc<Translator>,
 ) -> Box<dyn Fn(petgraph::prelude::NodeIndex, &'a RSsystem) -> String + 'a> {
     // The type cannot be aliased since rust doesnt like generics.
@@ -557,11 +560,43 @@ fn generate_node_pringting_fn<'a>(
                     (accumulator)(i, n)
                         + &graph::GraphMapNodesTy::from(d.clone(), val.clone()).get()(i, n)
                 })
-            }
+            },
             NodeDisplay::Separator(s) => {
                 // we have a string so simply add it at the end
                 Box::new(move |i, n| (accumulator)(i, n) + s)
-            }
+            },
+	    // ad hoc since graph information is not available in the graph
+	    // function generation
+	    NodeDisplay::UncommonEntities => {
+		let common_entities = graph::common_entities(graph);
+		let val = translator.clone();
+		Box::new(move |i, n| {
+		    (accumulator)(i, n)
+			+ &graph::GraphMapNodesTy::from(
+			    graph::GraphMapNodes::ExcludeEntities {
+				mask: common_entities.clone()
+			    },
+			    val.clone()
+			).get()(i, n)
+		    }
+		)
+	    },
+	    // ad hoc since graph information is not available in the graph
+	    // function generation
+	    NodeDisplay::MaskUncommonEntities(mask) => {
+		let common_entities = graph::common_entities(graph);
+		let val = translator.clone();
+		Box::new(move |i, n| {
+		    (accumulator)(i, n)
+			+ &graph::GraphMapNodesTy::from(
+			    graph::GraphMapNodes::ExcludeEntities {
+				mask: common_entities.union(mask)
+			    },
+			    val.clone()
+			).get()(i, n)
+		    }
+		)
+	    },
         };
     }
     accumulator
@@ -666,6 +701,7 @@ pub fn dot(
             // fine...
             let modified_graph = graph.map(
                 generate_node_pringting_fn(&node_display,
+					   graph,
 					   Rc::clone(&rc_translator)),
                 generate_edge_pringting_fn(&edge_display,
 					   Rc::clone(&rc_translator)),
@@ -707,6 +743,7 @@ pub fn graphml(
             // map each value to the corresponding value we want to display
             let modified_graph = graph.map(
                 generate_node_pringting_fn(&node_display,
+					   graph,
 					   Rc::clone(&rc_translator)),
                 generate_edge_pringting_fn(&edge_display,
 					   rc_translator),
diff --git a/src/rsprocess/structure.rs b/src/rsprocess/structure.rs
index d49b18e..b9ace77 100644
--- a/src/rsprocess/structure.rs
+++ b/src/rsprocess/structure.rs
@@ -11,7 +11,7 @@ use serde::{Deserialize, Serialize};
 // -----------------------------------------------------------------------------
 
 /// Basic set of entities.
-#[derive(Clone, Debug, PartialOrd, Eq, Ord, Hash, Serialize, Deserialize)]
+#[derive(Clone, Debug, PartialOrd, Eq, Ord, Serialize, Deserialize)]
 pub struct RSset {
     pub identifiers: BTreeSet<IdType>,
 }
@@ -79,7 +79,7 @@ impl RSset {
         RSset { identifiers: res }
     }
 
-    /// returns the new set a \ b
+    /// returns the new set a ∖ b
     pub fn subtraction(&self, b: &RSset) -> RSset {
         // TODO maybe find more efficient way without copy/clone
         let res: BTreeSet<_> = self
@@ -123,6 +123,12 @@ impl PartialEq for RSset {
     }
 }
 
+impl Hash for RSset {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+	self.identifiers.hash(state)
+    }
+}
+
 impl IntoIterator for RSset {
     type Item = IdType;
     type IntoIter = std::collections::btree_set::IntoIter<Self::Item>;
@@ -564,7 +570,8 @@ impl PartialEq for RSlabel {
     fn eq(&self, other: &Self) -> bool {
 	self.available_entities == other.available_entities &&
 	    self.context == other.context &&
-	    self.t == other.t &&
+	//  self.t == other.t && // no need since its the union of the above
+	//  // elements
 	    self.reactants == other.reactants &&
 	    self.reactants_absent == other.reactants_absent &&
 	    self.inhibitors == other.inhibitors &&